The BioMicro Center now supports preparation of Chromatin IP samples. Basics about Chromatin IP can be found at this link.
The Diagenode IP-star is a single purpose robot designed to handle IPs. The IP-Star has a throughput of 8 samples per day. The samples can vary on cell types, antibodies or buffer conditions, though the timing must remain constant. The system mixes the samples by repeatedly pipetting them. To separate the beads from the supernatant, the IP-Star works by placing a magnet next to the tips, retaining the beads in the tip while allowing the rest of the chromatin or washes to be removed. Once the sample is eluted from the beads, the beads are removed from the sample by keeping the beads in the tip again.
The IP-star requires 5 million cells per IP. It should work with many different cell lysis / crosslinking conditions but we have validated the protocol below:
Chromatin – Sonicated chromatin must be submitted at 5 million cells per 200uL volume. Antibodies must be submitted at the same time(at least 3ug of antibody per IP). We have done months of testing and highly recommend using the following sonication conditions:
1. Resuspend fixed cells in 10mL of LB1
2. Rock cells at 4 degrees for 10 minutes
3. Pellet cells at 4 degrees for 5 minutes at 1350g
4. Remove supernatant and resuspend cells in 10mL of LB2
5. Rock cells at 4 degrees for 10 minutes
6. Pellet cells at 4 degrees for 5 minutes at 1350g
7. Remove supernatant and resuspend cells in a volume of LB3 where there is 5 million cells/200uL
**Example: Resuspend 25 million cells in 1mL of LB3**
8. Sonicate cells
9. Pellet debris at 4 degrees for 10 minutes at 20,000g
10. Submit lysate for ChIP
Sonication conditions vary broadly between different cell types and different sonicators so you will want to optimize your conditions to produce material in the 100-500nt rage. We strongly recommend that you not freeze your lysate before submitting it for ChIP therefore, it is critical that you coordinate with BioMicro Center staff members to be sure that space is available on the IP-Star when your cells are ready.
Chromatin Immunoprecipitation Sequencing (ChIP-Seq) combines ChIP with DNA sequencing, allowing researchers to identify the binding sites of DNA-associated proteins. It can be used as a more cost effective and higher quality alternative to whole genome microarray hybridization. You can find more information about Illumina's ChIP-Seq protocols and kits here. ChIP-Seq samples are typically run as 36nt or 40nt single-end runs on the GAIIx or HiSeq, respectively.
ChIP Seq Literature
- Marson A, Levine SS, Cole MF, Frampton GM, Brambrink T, Johnstone S, Guenther MG, Johnston WK, Wernig M, Newman J, Calabrese JM, Dennis LM, Volkert TL, Gupta S, Love J, Hannett N, Sharp PA, Bartel DP, Jaenisch R, and Young RA. . pmid:18692474.
- Robertson G, Hirst M, Bainbridge M, Bilenky M, Zhao Y, Zeng T, Euskirchen G, Bernier B, Varhol R, Delaney A, Thiessen N, Griffith OL, He A, Marra M, Snyder M, and Jones S. . pmid:17558387.