Short-term memory in yeast cerevisiae

Gal1, a metabolic enzyme (galactokinase) expressed at high level during induction by galactose allows for maintenance of memory of a previous transcriptional for 6/7 generations. Gal1 presents high homology with Gal3, which sequester Gal80, repressor of the transcription factor Gal4, which act on Gal metabolism genes. Thus high levels of Gal1, induced during the first exposure to galactose, help the cell maintain memory of this first exposure by sequestring gal80, thus rendering the system more reactive to galactose exposition the second time. Dilution of Gal1 during successives cell divisions lead to the Loss of this memory.