Combinations of regulatory proteins control cell types MAT locus a2 at a2 a1 Expressed regulatory proteins a2 a1 a2 MCM1 MCM1 MCM1 a2 a2 a-specific genes ON OFF OFF MCM1 MCM1 MCM1 a1 a-specific genes OFF ON OFF MCM1 a1 a2 Haploid-specific ON ON OFF genes (a) a cell (b) a cell (c) ala cell FIGURE 12-10 Control of cell-type- specific gene expression in yeast. The three cell types of S. cerevisiae are determined by the regulatory proteins a1, a1, and a2, which regulate different subsets of target genes. The MCM1 protein acts in all three cell types and interacts with a1 and o2. In a diploid yeast cell, regulatory proteins encoded by each MAT locus are expressed (Figure 12-10c). What is the result? All the structural genes involved in cell mating are shut down, as are a separate set of genes, called haploid specific, that are expressed in haploid cells but not diploid cells. How does this happen? The a1 protein encoded by MAT has a part to play at last. The a1 protein can bind to some of the o2 protein present and alter its binding specificity such that the al-a2 com-

Combinations of regulatory proteins control cell types MAT locus a2 at a2 a1 Expressed regulatory proteins a2 a1 a2 MCM1 MCM1 MCM1 a2 a2 a-specific genes ON OFF OFF MCM1 MCM1 MCM1 a1 a-specific genes OFF ON OFF MCM1 a1 a2 Haploid-specific ON ON OFF genes (a) a cell (b) a cell (c) ala cell FIGURE 12-10 Control of cell-type- specific gene expression in yeast. The three cell types of S. cerevisiae are determined by the regulatory proteins a1, a1, and a2, which regulate different subsets of target genes. The MCM1 protein acts in all three cell types and interacts with a1 and o2. In a diploid yeast cell, regulatory proteins encoded by each MAT locus are expressed (Figure 12-10c). What is the result? All the structural genes involved in cell mating are shut down, as are a separate set of genes, called haploid specific, that are expressed in haploid cells but not diploid cells. How does this happen? The a1 protein encoded by MAT has a part to play at last. The a1 protein can bind to some of the o2 protein present and alter its binding specificity such that the al-a2 com-

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter9: Cell Communication

Section: Chapter Questions

Problem 2ITD

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