Inactive cassettes do not synthesize RNA 17.3 Yeast can switch ilent and active loci for mating type a HMRa Figure 17.6 Silent cassettes Active cassettes synthesize mating-ty pe-specific products have the same sequences as the corresponding active TAo cassettes, except for the 02 mrna c1 mRNA absence of the extreme Ya MATa flanking sequences in HMRa Only the Y region changes a 1 mRNA between a and a types 1000 1500 2000 消当
Figure 17.6 Silent cassettes have the same sequences as the corresponding active cassettes, except for the absence of the extreme flanking sequences in HMRa. Only the Y region changes between a and a types. 17.3 Yeast can switch silent and active loci for mating type
17.3 Yeast can switch silent and active loci for mating type a specific a specific haploid function No known funcions constitution a) sdacs e diploid not repressed expressed expressed "(∞ Represses haploid/pressed inducedconstitutive Inctions Figure 17.7 In diploids the al and a2 proteins cooperate to repress haploid-specific functions. In a haploids, mating functions are constitutive. In a haploids, the a2 protein represses a mating functions, while al induces a mating functions 请莘大
Figure 17.7 In diploids the a1 and a2 proteins cooperate to repress haploid-specific functions. In a haploids, mating functions are constitutive. In a haploids, the a2 protein represses a mating functions, while a1 induces a mating functions. 17.3 Yeast can switch silent and active loci for mating type
17.3 Yeast can switch silent and active loci for mating type a-specific genes ak-speafic genes PRTF activates genes constitut ively Genes off: PRTF cannot bind without a1 Figure 17.8 Combinations of (PRTF PRTF) (PRTF) a haploid CCATGTAATTACCCAAAAAGGAAATTTACATGG TTTCCTAATTAGTNONTCAAT GNCAG PrTE al al and a2 activate or +PRTF repress a-specific genes o1 enables PRTF to activate target genes repress specITIc PRTF PRTF)(ad1 o% haploid TTTCCTAAT TAGTNONTCAATGNCAG groups of genes to correspond with CCATGTAATTACCCAAAAAGGAAATT TACATGG the mating type of 42+ a1 repress haploid-spedific genes the cell 消当 COATGTNANT NNTACATGG
Figure 17.8 Combinations of PRTF, a1, a1 and a2 activate or repress specific groups of genes to correspond with the mating type of the cell. 17.3 Yeast can switch silent and active loci for mating type
an d covers 75-envp Sins sigma In itiat on complex cont 9.4 Sigma factor 50-40-50-20-101+10+20+30 controls binding tO DNA 入0 I nitial ebngation complex farms at 10 bases. lases sgma, ad loses cantans in-3 to 55 regan 50-40-50-20-101+10+20+30 Figure 9.10 RNA polymerase initially contacts the region from-55 to +20. When sigma dissociates. the core enzyme contracts to-30: when the General elongation complex enzyme moves a few base foms at 15-20 bases and covers 30-40 bp pairs, it becomes more 0-40-30-20-10 +10+20+30 compactly organized into the general elongation complex 消当
Figure 9.10 RNA polymerase initially contacts the region from -55 to +20. When sigma dissociates,the core enzyme contracts to -30; when the enzyme moves a few base pairs, it becomes more compactly organized into the general elongation complex. 9.4 Sigma factor controls binding to DNA
17.4 Silent cassettes at HML and HMR are repressed Inactive cassettes do not synthesize RNA Yo Figure 17.6 Silent cassettes have the same a HMRal sequences as the Active cassettes synthesize corresponding active mating-ty pe-specific products cassettes, except for the A70 absence of the extreme flanking sequences in 2 mrNa c1 mRNA HMRa. Only the y MATa region changes between a and a types a 1 mRNA 消当 500 1000 1500 2000
Figure 17.6 Silent cassettes have the same sequences as the corresponding active cassettes, except for the absence of the extreme flanking sequences in HMRa. Only the Y region changes between a and a types. 17.4 Silent cassettes at HML and HMR are repressed