Brianna N. Samuels-Week 4/5

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Purpose

to practice statistal analysis of data using Microsoft Excel and Dr. Dahlquist's Data

Materials and Methods

Before Starting the Statistical Analysis

  • This assignment will be analyzing the yeast strains: wild-type, dGLN3, dHAP4, and dZAP1.
  • My assignment specifically will focus on the dHAP4 yeast strain.
  • Filename of the master Excel sheet used: BIOL338_S19_microarray-data_dHAP4
  • Below are the type-points used to collect data, along with their number of replicates:
    • The time-points, signified by (t#) were 15 minutes, 30 minutes, 60 minutes, 90 minutes, and 120 minutes.
    • Time-points t15, t30, and t60 had four replicates, while t90 and t120 had 3 replicates.

Statistical Analysis Part 1: ANOVA

The purpose of the witin-stain ANOVA test is to determine if any genes had a gene expression change that was significantly different than zero at any timepoint.

  1. Create a new worksheet, naming it either "(dHAP4)_ANOVA" as appropriate.
  2. Copy the first three columns containing the "MasterIndex", "ID", and "Standard Name" from the "Master_Sheet" worksheet for your strain and paste it into your new worksheet. Copy the columns containing the data for your strain and paste it into your new worksheet.
  3. At the top of the first column to the right of your data, create five column headers of the form (dHAP4)_AvgLogFC_(TIME) where (dHAP4) is your strain designation and (TIME) is 15, 30, 60,90, and 120
  4. In the cell below the (dHAP4)_AvgLogFC_t15 header, type =AVERAGE(
  5. Then highlight all the data in row 2 associated with (dHAP4) and t15, press the closing paren key (shift 0),and press the "enter" key.
  6. This cell now contains the average of the log fold change data from the first gene at t=15 minutes.
  7. Click on this cell and position your cursor at the bottom right corner. You should see your cursor change to a thin black plus sign (not a chubby white one). When it does, double click, and the formula will magically be copied to the entire column of 6188 other genes.
  8. Repeat steps (4) through (8) with the t30, t60, t90, and the t120 data.
  9. Now in the first empty column to the right of the (dHAP4)_AvgLogFC_t120 calculation, create the column header (dHAP4)_ss_HO.
  10. In the first cell below this header, type =SUMSQ(
  11. Highlight all the LogFC data in row 2 for your (dHAP4) (but not the AvgLogFC), press the closing paren key (shift 0),and press the "enter" key.
  12. In the next empty column to the right of (dHAP4)_ss_HO, create the column headers (dHAP4)_ss_(TIME) as in (3).
  13. Make a note of how many data points you have at each time point for your strain.
  14. In the first cell below the header (dHAP4)_ss_t15, type =SUMSQ(<range of cells for logFC_t15>)-COUNTA(<range of cells for logFC_t15>)*<AvgLogFC_t15>^2 and hit enter.
    • The COUNTA function counts the number of cells in the specified range that have data in them (i.e., does not count cells with missing values).
    • The phrase <range of cells for logFC_t15> should be replaced by the data range associated with t15.
    • The phrase <number of data points> should be replaced by the number of data points for that timepoint
    • The phrase <AvgLogFC_t15> should be replaced by the cell number in which you computed the AvgLogFC for t15, and the "^2" squares that value.
    • Upon completion of this single computation, use the Step (7) trick to copy the formula throughout the column.
  15. Repeat this computation for the t30 through t120 data points. Again, be sure to get the data for each time point, type the right number of data points, and get the average from the appropriate cell for each time point, and copy the formula to the whole column for each computation.
  16. In the first column to the right of (dHAP4)_ss_t120, create the column header (dHAP4)_SS_full.
  17. In the first row below this header, type =sum(<range of cells containing "ss" for each timepoint>) and hit enter.
  18. In the next two columns to the right, create the headers (STRAIN)_Fstat and (dHAP4)_p-value.
  19. Recall the number of data points from (13): call that total n (which is 18).
  20. In the first cell of the (dHAP4)_Fstat column, type =((18-5)/5)*(<(dHAP4)_ss_HO>-<(STRAIN)_SS_full>)/<(dHAP4)_SS_full> and hit enter.
    • Copy to the whole column.
  21. In the first cell below the (dHAP4)_p-value header, type =FDIST(<(STRAIN)_Fstat>,5,n-5) replacing the phrase <(dHAP4)_Fstat> with the cell designation and the "n" (18) with the number of data points total. Copy to the whole column.
  22. Before we move on to the next step, we will perform a quick sanity check to see if we did all of these computations correctly.
    • Click on cell A1 and click on the Data tab. Select the Filter icon (looks like a funnel). Little drop-down arrows should appear at the top of each column. This will enable us to filter the data according to criteria we set.
    • Click on the drop-down arrow on your (dHAP4)_p-value column. Select "Number Filters". In the window that appears, set a criterion that will filter your data so that the p value has to be less than 0.05.
    • Excel will now only display the rows that correspond to data meeting that filtering criterion. A number will appear in the lower left hand corner of the window giving you the number of rows that meet that criterion. We will check our results with each other to make sure that the computations were performed correctly.\

Calculate the Bonferroni and p value Correction

  1. Now we will perform adjustments to the p value to correct for the multiple testing problem. Label the next two columns to the right with the same label, (dHAP4)_Bonferroni_p-value.
  2. Type the equation =<(dHAP4)_p-value>*6189, Upon completion of this single computation, use the Step (10) trick to copy the formula throughout the column.
  3. Replace any corrected p value that is greater than 1 by the number 1 by typing the following formula into the first cell below the second (dHAP4)_Bonferroni_p-value header: =IF(dHAP4_Bonferroni_p-value>1,1,dHAP4_Bonferroni_p-value), where "dHAP4_Bonferroni_p-value" refers to the cell in which the first Bonferroni p value computation was made. Use the Step (10) trick to

copy the formula throughout the column.

Calculate the Benjamini & Hochberg p value Correction

  1. Insert a new worksheet named "(dHAP4)_ANOVA_B-H".
  2. Copy and paste the "MasterIndex", "ID", and "Standard Name" columns from your previous worksheet into the first two columns of the new worksheet.
  3. For the following, use Paste special > Paste values. Copy your unadjusted p values from your ANOVA worksheet and paste it into Column D.
  4. Select all of columns A, B, C, and D. Sort by ascending values on Column D. Click the sort button from A to Z on the toolbar, in the window that appears, sort by column D, smallest to largest.
  5. Type the header "Rank" in cell E1. We will create a series of numbers in ascending order from 1 to 6189 in this column. This is the p value rank, smallest to largest. Type "1" into cell E2 and "2" into cell E3. Select both cells E2 and E3. Double-click on the plus sign on the lower right-hand corner of your selection to fill the column with a series of numbers from 1 to 6189.
  6. Now you can calculate the Benjamini and Hochberg p value correction. Type (dHAP4)_B-H_p-value in cell F1. Type the following formula in cell F2: =(D2*6189)/E2 and press enter. Copy that equation to the entire column.
  7. Type "dHAP4_B-H_p-value" into cell G1.
  8. Type the following formula into cell G2: =IF(F2>1,1,F2) and press enter. Copy that equation to the entire column.
  9. Select columns A through G. Now sort them by your MasterIndex in Column A in ascending order.
  10. Copy column G and use Paste special > Paste values to paste it into the next column on the right of your ANOVA sheet.
  • Upload the .xlsx file that you have just created to Box. Send Dr. Dahlquist and Dr. Fitzpatrick an e-mail with the link to the file (e-mail kdahlquist or bfitzpatrick at lmu dot edu).

Sanity Check: Number of genes significantly changed

Before we move on to further analysis of the data, we want to perform a more extensive sanity check to make sure that we performed our data analysis correctly. We are going to find out the number of genes that are significantly changed at various p value cut-offs.

  • Go to your (dHAP4)_ANOVA worksheet.
  • Select row 1 (the row with your column headers) and select the menu item Data > Filter > Autofilter (The funnel icon on the Data tab). Little drop-down arrows should appear at the top of each column. This will enable us to filter the data according to criteria we set.
  • Click on the drop-down arrow for the unadjusted p value. Set a criterion that will filter your data so that the p value has to be less than 0.05.
    • How many genes have p < 0.05? and what is the percentage (out of 6189)?
    • How many genes have p < 0.01? and what is the percentage (out of 6189)?
    • How many genes have p < 0.001? and what is the percentage (out of 6189)?
    • How many genes have p < 0.0001? and what is the percentage (out of 6189)?
  • When we use a p value cut-off of p < 0.05, what we are saying is that you would have seen a gene expression change that deviates this far from zero by chance less than 5% of the time.
  • We have just performed 6189 hypothesis tests. Another way to state what we are seeing with p < 0.05 is that we would expect to see this a gene expression change for at least one of the timepoints by chance in about 5% of our tests, or 309 times. Since we have more than 309 genes that pass this cut off, we know that some genes are significantly changed. However, we don't know which ones. To apply a more stringent criterion to our p values, we performed the Bonferroni and Benjamini and Hochberg corrections to these unadjusted p values. The Bonferroni correction is very stringent. The Benjamini-Hochberg correction is less stringent. To see this relationship, filter your data to determine the following:
    • How many genes are p < 0.05 for the Bonferroni-corrected p value? and what is the percentage (out of 6189)?
    • How many genes are p < 0.05 for the Benjamini and Hochberg-corrected p value? and what is the percentage (out of 6189)?
  • In summary, the p value cut-off should not be thought of as some magical number at which data becomes "significant". Instead, it is a moveable confidence level. If we want to be very confident of our data, use a small p value cut-off. If we are OK with being less confident about a gene expression change and want to include more genes in our analysis, we can use a larger p value cut-off.
  • Comparing results with known data: the expression of the gene NSR1 (ID: YGR159C)is known to be induced by cold shock. Find NSR1 in your dataset. What is its unadjusted, Bonferroni-corrected, and B-H-corrected p values? What is its average Log fold change at each of the timepoints in the experiment? Note that the average Log fold change is what we called "dHAP4)_AvgLogFC_(TIME)" in step 3 of the ANOVA analysis.
  • We will compare the numbers we get between the wild type strain and the other strains studied, organized as a table. Use this sample PowerPoint slide to see how your table should be formatted. (Note that you will need to unzip the file after downloading.)

Clustering and GO Term Enrichment with stem (part 2)

  1. Prepare your microarray data file for loading into STEM. Have this part completed for Tuesday, February 19.
    • Insert a new worksheet into your Excel workbook, and name it "(dHAP4)_stem".
    • Select all of the data from your "(dHAP4)_ANOVA" worksheet and Paste special > paste values into your "(dHAP4)_stem" worksheet.
      • Your leftmost column should have the column header "Master_Index". Rename this column to "SPOT". Column B should be named "ID". Rename this column to "Gene Symbol". Delete the column named "Standard_Name".
      • Filter the data on the B-H corrected p value to be > 0.05 (that's greater than in this case).
        • Once the data has been filtered, select all of the rows (except for your header row) and delete the rows by right-clicking and choosing "Delete Row" from the context menu. Undo the filter. This ensures that we will cluster only the genes with a "significant" change in expression and not the noise.
      • Delete all of the data columns EXCEPT for the Average Log Fold change columns for each timepoint (for example, wt_AvgLogFC_t15, etc.).
      • Rename the data columns with just the time and units (for example, 15m, 30m, etc.).
      • Save your work. Then use Save As to save this spreadsheet as Text (Tab-delimited) (*.txt). Click OK to the warnings and close your file.
        • Note that you should turn on the file extensions if you have not already done so.
  2. Now download and extract the STEM software. Click here to go to the STEM web site.
    • Click on the download link and download the stem.zip file to your Desktop.
    • Unzip the file. In Seaver 120, you can right click on the file icon and select the menu item 7-zip > Extract Here.
    • This will create a folder called stem.
    • Inside the folder, double-click on the stem.jar to launch the STEM program.
  3. Running STEM
    1. In section 1 (Expression Data Info) of the the main STEM interface window, click on the Browse... button to navigate to and select your file.
      • Click on the radio button No normalization/add 0.
      • Check the box next to Spot IDs included in the data file.
    2. In section 2 (Gene Info) of the main STEM interface window, leave the default selection for the three drop-down menu selections for Gene Annotation Source, Cross Reference Source, and Gene Location Source as "User provided".
    3. Click the "Browse..." button to the right of the "Gene Annotation File" item. Browse to your "stem" folder and select the file "gene_association.sgd.gz" and click Open.
    4. In section 3 (Options) of the main STEM interface window, make sure that the Clustering Method says "STEM Clustering Method" and do not change the defaults for Maximum Number of Model Profiles or Maximum Unit Change in Model Profiles between Time Points.
    5. In section 4 (Execute) click on the yellow Execute button to run STEM.
  4. Viewing and Saving STEM Results
    1. A new window will open called "All STEM Profiles (1)". Each box corresponds to a model expression profile. Colored profiles have a statistically significant number of genes assigned; they are arranged in order from most to least significant p value. Profiles with the same color belong to the same cluster of profiles. The number in each box is simply an ID number for the profile.
      • Click on the button that says "Interface Options...". At the bottom of the Interface Options window that appears below where it says "X-axis scale should be:", click on the radio button that says "Based on real time". Then close the Interface Options window.
      • Take a screenshot of this window (on a PC, simultaneously press the Alt and PrintScreen buttons to save the view in the active window to the clipboard) and paste it into a PowerPoint presentation to save your figures.
    2. Click on each of the SIGNIFICANT profiles (the colored ones) to open a window showing a more detailed plot containing all of the genes in that profile.
      • Take a screenshot of each of the individual profile windows and save the images in your PowerPoint presentation.
      • At the bottom of each profile window, there are two yellow buttons "Profile Gene Table" and "Profile GO Table". For each of the profiles, click on the "Profile Gene Table" button to see the list of genes belonging to the profile. In the window that appears, click on the "Save Table" button and save the file to your desktop. Make your filename descriptive of the contents, e.g. "dHAP4_45_genelist.txt"
        • Upload these files to OpenWetWare and link to them on your individual journal page. (Note that it will be easier to zip all the files together and upload them as one file).
      • For each of the significant profiles, click on the "Profile GO Table" to see the list of Gene Ontology terms belonging to the profile. In the window that appears, click on the "Save Table" button and save the file to your desktop. Make your filename descriptive of the contents, e.g. "dHAP4_45_GOlist.txt" At this point you have saved all of the primary data from the STEM software and it's time to interpret the results!
        • Upload these files to OpenWetWare and link to them on your individual journal page. (Note that it will be easier to zip all the files together and upload them as one file).
  5. Analyzing and Interpreting STEM Results
    1. Select one of the profiles you saved in the previous step for further intepretation of the data. I suggest that you choose one that has a pattern of up- or down-regulated genes at the cold shock timepoints. Each member of your group should choose a different profile. Answer the following:
      • Why did you select this profile? In other words, why was it interesting to you?
      • How many genes belong to this profile?
      • How many genes were expected to belong to this profile?
      • What is the p value for the enrichment of genes in this profile? Bear in mind that we just finished computing p values to determine whether each individual gene had a significant change in gene expression at each time point. This p value determines whether the number of genes that show this particular expression profile across the time points is significantly more than expected.
      • Open the GO list file you saved for this profile in Excel. This list shows all of the Gene Ontology terms that are associated with genes that fit this profile. Select the third row and then choose from the menu Data > Filter > Autofilter. Filter on the "p-value" column to show only GO terms that have a p value of < 0.05. How many GO terms are associated with this profile at p < 0.05? The GO list also has a column called "Corrected p-value". This correction is needed because the software has performed thousands of significance tests. Filter on the "Corrected p-value" column to show only GO terms that have a corrected p value of < 0.05. How many GO terms are associated with this profile with a corrected p value < 0.05?
      • Select 6 Gene Ontology terms from your filtered list (either p < 0.05 or corrected p < 0.05).
        • Each member of the group will be reporting on his or her own cluster in your research presentation. You should take care to choose terms that are the most significant, but that are also not too redundant. For example, "RNA metabolism" and "RNA biosynthesis" are redundant with each other because they mean almost the same thing.
          • Note whether the same GO terms are showing up in multiple clusters.
        • Look up the definitions for each of the terms at http://geneontology.org. In your research presentation, you will discuss the biological interpretation of these GO terms. In other words, why does the cell react to cold shock by changing the expression of genes associated with these GO terms? Also, what does this have to do with the transcription factor being deleted (for the Δgln3 and Δswi4 groups)?
        • To easily look up the definitions, go to http://geneontology.org.
        • Copy and paste the GO ID (e.g. GO:0044848) into the search field on the left of the page.
        • In the results page, click on the button that says "Link to detailed information about <term>, in this case "biological phase"".
        • The definition will be on the next results page, e.g. here.

Using YEASTRACT to Infer which Transcription Factors Regulate a Cluster of Genes (Tuesday, Feb. 19)

In the previous analysis using STEM, we found a number of gene expression profiles (aka clusters) which grouped genes based on similarity of gene expression changes over time. The implication is that these genes share the same expression pattern because they are regulated by the same (or the same set) of transcription factors. We will explore this using the YEASTRACT database.

  1. Open the gene list in Excel for the one of the significant profiles from your stem analysis. Choose a cluster with a clear cold shock/recovery up/down or down/up pattern. You should also choose one of the largest clusters.
    • Copy the list of gene IDs onto your clipboard.
  2. Launch a web browser and go to the YEASTRACT database.
    • On the left panel of the window, click on the link to Rank by TF.
    • Paste your list of genes from your cluster into the box labeled ORFs/Genes.
    • Check the box for Check for all TFs.
    • Accept the defaults for the Regulations Filter (Documented, DNA binding plus expression evidence)
    • Do not apply a filter for "Filter Documented Regulations by environmental condition".
    • Rank genes by TF using: The % of genes in the list and in YEASTRACT regulated by each TF.
    • Click the Search button.
  3. Answer the following questions:
    • In the results window that appears, the p values colored green are considered "significant", the ones colored yellow are considered "borderline significant" and the ones colored pink are considered "not significant". How many transcription factors are green or "significant"?
    • Copy the table of results from the web page and paste it into a new Excel workbook to preserve the results.
      • Upload the Excel file to OWW or Box and link to it in your electronic lab notebook.
      • Are GLN3, HAP4, and/or ZAP1 on the list? If so, what is their "% in user set", "% in YEASTRACT", and "p value".
  4. For the mathematical model that we will build, we need to define a gene regulatory network of transcription factors that regulate other transcription factors. We can use YEASTRACT to assist us with creating the network. We want to generate a network with approximately 15-20 transcription factors in it.
    • You need to select from this list of "significant" transcription factors, which ones you will use to run the model. You will use these transcription factors and add GLN3, HAP4, and ZAP1 if they are not in your list. Explain in your electronic notebook how you decided on which transcription factors to include. Record the list and your justification in your electronic lab notebook. Each group member will select a different network (they can have some overlapping transcription factors, but some should also be different).
    • Go back to the YEASTRACT database and follow the link to Generate Regulation Matrix.
    • Copy and paste the list of transcription factors you identified (plus HAP4, GLN3, and ZAP1) into both the "Transcription factors" field and the "Target ORF/Genes" field.
    • We are going to use the "Regulations Filter" options of "Documented", "Only DNA binding evidence"
      • Click the "Generate" button.
      • In the results window that appears, click on the link to the "Regulation matrix (Semicolon Separated Values (CSV) file)" that appears and save it to your Desktop. Rename this file with a meaningful name so that you can distinguish it from the other files you will generate.

Visualizing Your Gene Regulatory Networks with GRNsight (Tuesday, Feb. 19)

We will analyze the regulatory matrix files you generated above in Microsoft Excel and visualize them using GRNsight to determine which one will be appropriate to pursue further in the modeling.

  1. First we need to properly format the output files from YEASTRACT.
    • Open the file in Excel. It will not open properly in Excel because a semicolon was used as the column delimiter instead of a comma. To fix this, Select the entire Column A. Then go to the "Data" tab and select "Text to columns". In the Wizard that appears, select "Delimited" and click "Next". In the next window, select "Semicolon", and click "Next". In the next window, leave the data format at "General", and click "Finish". This should now look like a table with the names of the transcription factors across the top and down the first column and all of the zeros and ones distributed throughout the rows and columns. This is called an "adjacency matrix." If there is a "1" in the cell, that means there is a connection between the trancription factor in that row with that column.
    • Save this file in Microsoft Excel workbook format (.xlsx).
    • For this adjacency matrix to be usable in GRNmap (the modeling software) and GRNsight (the visualization software), we need to transpose the matrix. Insert a new worksheet into your Excel file and name it "network". Go back to the previous sheet and select the entire matrix and copy it. Go to you new worksheet and click on the A1 cell in the upper left. Select "Paste special" from the "Home" tab. In the window that appears, check the box for "Transpose". This will paste your data with the columns transposed to rows and vice versa. This is necessary because we want the transcription factors that are the "regulatORS" across the top and the "regulatEES" along the side.
    • The labels for the genes in the columns and rows need to match. Thus, delete the "p" from each of the gene names in the columns. Adjust the case of the labels to make them all upper case.
    • In cell A1, copy and paste the text "rows genes affected/cols genes controlling".
    • Finally, for ease of working with the adjacency matrix in Excel, we want to alphabatize the gene labels both across the top and side.
      • Select the area of the entire adjacency matrix.
      • Click the Data tab and click the custom sort button.
      • Sort Column A alphabetically, being sure to exclude the header row.
      • Now sort row 1 from left to right, excluding cell A1. In the Custom Sort window, click on the options button and select sort left to right, excluding column 1.
    • Name the worksheet containing your organized adjacency matrix "network" and Save.
  2. Now we will visualize what these gene regulatory networks look like with the GRNsight software.
    • Go to the GRNsight home page.
    • Select the menu item File > Open and select the regulation matrix .xlsx file that has the "network" worksheet in it that you formatted above. If the file has been formatted properly, GRNsight should automatically create a graph of your network. You can click the "Grid Layout" button to arrange the nodes in a grid, or you can click and drag the nodes (genes) around until you get a layout that you like and take a screenshot of the results. Paste it into your PowerPoint presentation.
      • If you have nodes (genes) floating around in the display that are not connected to any other nodes, we need to delete them from the network for the modeling to work properly. Go back to the Excel workbook and network sheet and delete both the row and column with the floating gene's name. Then re-upload the edited file to GRNsight to visualize it. Use this final version in your PowerPoint and subsequent modeling.

Summary of what you need to turn in for the individual Weeks 4 and 5 assignments

You will continue working on your Week 4 individual journal page for the Week 5 assignment as well. The two assignments will be graded together after the Week 5 due date for 20 points, instead of individually for 10 points each.

By the Week 4 deadline, submit:

  1. Your individual journal page should have an electronic lab notebook recording your work for this week. This includes the purpose, detailed methods, your results, the answers to any questions posed in the protocol above, a scientific conclusion, and the acknowledgments and references sections. You are responsible for completing the procedure up to the designated stopping point.
  2. Upload your updated Excel spreadsheet to Box that has today's calculations in it. Use the same filename as before so that the download link that you already provided to Drs. Dahlquist and Fitzpatrick will still work.
  3. Create, upload to OpenWetWare, and link to a PowerPoint presentation that contains the p value table. You will need to zip it because OWW does not accept .ppt or .pptx as a file format anymore.

By the Week 5 deadline, submit:

  1. Continuation of the individual journal page for Week 4 with your electronic lab notebook recording your work for the last two weeks. This includes the purpose, detailed methods, your results, the answers to any questions posed in the protocol above, a scientific conclusion, and the acknowledgments and references sections. You will add to what you submitted to the interim deadline on Week 4. Don't forget your paragraph which is a biological interpretation of your stem results.
  2. Add the screenshots of your stem results and GRNsight visualization to the PowerPoint file from last week. Do not change the filename, just upload a newer version of the file. Each slide in the presentation should have a meaningful title that describes the main message of the slide. These slides will form the basis of your research presentation for this project.
  3. Zip together all of the tab-delimited text files that you created for and from stem and upload them to Box:
    • the .txt file that was saved from your original spreadsheet that you used to run stem
    • each of the genelist and GOlist files for each of your significant profiles.
    • You will have a revised version of the main data analysis Excel workbook with additional sheets for the stem input, YEASTRACT rank by TF output, and GRNsight network.
  4. The shared journal assignment below.

Results

Week 4

p values less than 0.05

  • 2479/6189

p values less than 0.01

  • 1583/6189

p values less than 0.001

  • 739/6189

p values less than 0.0001

  • 280/6189

bonferroni p value less than 0.05

  • 75/6189

bonferroni-h p value less than o.05

  • 1735/6189

File:BIOL388 S19 sample p-value slide.pdf

media:BIOL388_S19_sample_p-value_slide_dHAP4.pdf

Week 5

media:BIOL388_S19_microarray-data_dHAP4.xlsx BS.zip

dHAP4 GOlist

dHAP4 Gene list

Powerpoint of Profile Pictures

media:YEASTRACT_TABLE.zip

media:Regulation_Matrix_1_bs.zip


  • I selected profile 45 because the p-value was very significant and had over 150 assigned genes.
  • 354 genes assigned
  • 44.3 expected genes
  • p-value was 2.9E-201
  • p<0.05 had 272/811
  • corrected p<0.05 had 45/811
  • RNA biosynthetic process
    • The chemical reactions and pathways resulting in the formation of RNA, ribonucleic acid, one of the two main type of nucleic acid, consisting of a long, unbranched macromolecule formed from ribonucleotides joined in 3',5'-phosphodiester linkage. Includes polymerization of ribonucleotide monomers. Refers not only to transcription but also to e.g. viral RNA replication.
    • since this results in the formation of RNA, transcription is required. Since some of the transcription factors are deleted, that means that transcription won't occur.
  • mannose transport
    • The process in which mannose is transported across a lipid bilayer, from one side of a membrane to the other. Mannose is the aldohexose manno-hexose, the C-2 epimer of glucose. The D-(+)-form is widely distributed in mannans and hemicelluloses and is of major importance in the core oligosaccharide of N-linked oligosaccharides of glycoproteins.
    • glucose plays a role in transcription so if glucose is present, that means that cAMP levels are low which means that CAP isn't bound to DNA causing no transcription. Since transcription factors are deleted that means that transcription won't occur regularly
  • glucose transmembrane transporter activity
    • Enables the transfer of the hexose monosaccharide glucose from one side of a membrane to the other
  • cell part
    • Any constituent part of a cell, the basic structural and functional unit of all organisms
  • regulation of gene expression
    • Any process that modulates the frequency, rate or extent of gene expression. Gene expression is the process in which a gene's coding sequence is converted into a mature gene product or products (proteins or RNA). This includes the production of an RNA transcript as well as any processing to produce a mature RNA product or an mRNA or circRNA (for protein-coding genes) and the translation of that mRNA or circRNA into protein. Protein maturation is included when required to form an active form of a product from an inactive precursor form.
  • nitrogen compound metabolic process
    • The chemical reactions and pathways involving organic or inorganic compounds that contain nitrogen
    • nitrogen is needed to synthesize proteins so if a cold shock occurs and transcription is disrupted, the proper mRNA strands that can code for protein can have issues
  • there are about 24 significant transcription factors
  • gln3=30.46%
  • hap4=18.10%
  • zap1=28.74%

Scientific Conclusion

The purpose was to analyze data from a microarray of data from yeast. Statistical analysis through ANOVA tests were ran to calculate p-values, Bonferroni p-values and Benjamini-Hochberg p-values to get more stringent values. With this information, we now see that the majority of the genes had p-values less than 0.05 prior to the data being adjusted. In week 5, we used STEM, GSNsight, and YEASTRACT to identify which transcription factors in our dHAP4 strain could be identified. We noticed that out of all the data, only 7 out of the 50 profiles were significant. Profiles 2, 9, and 22 were repressed during cold shock and induced during the recovery stages while the other 4 were induced during cold shock and repressed during the recovery stages. Our group split up the different profiles and I picked profile 45. It had plenty of genes assigned and a very significant p-value so it seemed like a good one to use. When I used the YEASTRACT software, I saw that 24 of my genes were significant, one of them including GLN3. My ZAP1 ended up being mildly significant (yellow) and HAP4 was not significant (pink).

Acknowledgements

  • Homework Partners: Desiree Gonzalez and Ava Lekander We met face-to-face in the computer lab and worked on sanity check as well as other individual questions on how to fulfill some of the steps prior to the sanity check. We also communicated through text. We met the following week as well face to face and worked on creating the clusters together and using YEASTRACT.
  • copied wiki syntax from Desiree Gonzalez
  • Asked for help on sorting from Dr. Dahlquist
  • "Except for what is noted above, this individual journal entry was completed by me and not copied from another source."

Briannansamuels (talk) 22:27, 20 February 2019 (PST)

References

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