Unformatted text preview: e if the other copy is regulated in the
e. How could you determine if there are sites in the
DNA 5 ¿ to the H2A coding sequence that are
responsible for the cell-cycle transcriptional
f. HIR2 and HIR3 are two genes that were identiﬁed
as regulators of transcription of the histone genes
based on the properties of mutations in these
genes. Null mutations in either gene lead to constitutive expression of H2A-H2B. Do HIR2 and
HIR3 encode positive or negative regulators?
g. Histone gene transcription is also sensitive to the
number of copies of the histone genes in the cell.
Introduction of a high copy number plasmid containing H2A and H2B into the cell will repress
transcription of H2A and H2B. How could you determine if the copy number control of transcription
is dependent on HIR2 and HIR3? Answer:
This problem involves molecular analysis of gene
structure and expression and the use of mutants to determine the role of a gene.
a. Because histones have such an essential role in
packaging DNA in the cell, you might predict...
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- Spring '08
- DNA, MAT locus, Yeast Geneticist