Question

To answer the next set of question you need to imagine how asg, hsg and asg expression might change in the three yeast cell types in the absence of the listed protein. If you imagine that the steady state levels of mRNA will increase in the absence of the protein then you would say it functions as a repressor. If you imagine that the steady state levels of mRNA will decrease in the absence of the protein then you would say it functions as an activator 7. Based on the models provided, which protein(s) play a role in transcriptional activation (circle all that apply). i MCMI ii. MATal iii. MATal iv. MATA2 8. Based on the models provided, which protein(s) play a role in transcriptional repression (circle all that apply). i MCMI. ii. MATal. iii. MATal iv. MAT2 9. Brainstorm about general lessons learned from the above information (I can think of two) 10. Recall, MCMI appears to encode a transcriptional activator with two well-characterized domains providing important functionality including a DNA binding domain and an acidic domain (which recruits RNA polymerase to the promoter to promote transcription). What other protein abilities (functionality) must MCMI have! All of MCMI abilities are encoded in the amino acid sequence. Which ability is likely nonfunction in the special mutant allele (mcml-1) described in lecture!

Answer 1

7) MCMI, MAT alpha 1, MAT alpha 2

8) MAT a1

9) Transcriptional regulation directly influences many biological phenomena such as cell growth, response to environmental change, development of multicellular organisms, and disease. Transcriptional regulatory mechanisms are fundamentally similar in eukaryotic organisms . Components of the basic RNA polymerase II (Pol II) machinery are highly conserved and, in some cases, functionally interchangeable. Transcription factors with similar structures and DNA-binding specificities are found throughout the eukaryotic kingdom, and acidic activation domains stimulate transcription across a wide range of species. Complex promoters with multiple protein binding sites are typical in all eukaryotic organisms, and efficient transcription generally requires the combinatorial and synergistic action of activator proteins that function at long and variable distances from the mRNA initiation site. Molecular mechanisms of eukaryotic transcriptional regulation have been elucidated from the studies that involve a wide variety of genes, promoters, proteins, organisms, and experimental approaches.