You have isolated two different mutants (reg1 andreg2) causing constitutive expression of the emu operon (emu1 emu2). One mutant contains a defect in aDNA-binding site, and the other has a loss-of-functiondefect in the gene encoding a protein that binds tothe site.a. Is the DNA-binding protein a positive or negativeregulator of gene expression?b. To determine which mutant has a defect in the siteand which one has a mutation in the binding protein, you decide to do an analysis using F′ plasmids. Assuming you can assay levels of the Emu1and Emu2 proteins, what results do you predict forthe two strains (i and ii; see descriptions below) ifreg2 encodes the regulatory protein and reg1 is theregulatory site?i. F′ (reg1−reg2+emu1−emu2+)/reg1+reg2+emu1+emu2−ii. F′ (reg1+reg2−emu1−emu2+)/reg1+reg2+emu1+emu2−c. What results do you predict for the two strains(i and ii) if reg1 encodes the regulatory proteinand reg2 is the regulatory site?
Gene Interactions
When the expression of a single trait is influenced by two or more different non-allelic genes, it is termed as genetic interaction. According to Mendel's law of inheritance, each gene functions in its own way and does not depend on the function of another gene, i.e., a single gene controls each of seven characteristics considered, but the complex contribution of many different genes determine many traits of an organism.
Gene Expression
Gene expression is a process by which the instructions present in deoxyribonucleic acid (DNA) are converted into useful molecules such as proteins, and functional messenger ribonucleic (mRNA) molecules in the case of non-protein-coding genes.
You have isolated two different mutants (reg1 and
reg2) causing constitutive expression of the emu operon (emu1 emu2). One mutant contains a defect in a
DNA-binding site, and the other has a loss-of-function
defect in the gene encoding a protein that binds to
the site.
a. Is the DNA-binding protein a positive or negative
regulator of gene expression?
b. To determine which mutant has a defect in the site
and which one has a mutation in the binding protein, you decide to do an analysis using F′ plasmids. Assuming you can assay levels of the Emu1
and Emu2 proteins, what results do you predict for
the two strains (i and ii; see descriptions below) if
reg2 encodes the regulatory protein and reg1 is the
regulatory site?
i. F′ (reg1−reg2+emu1−emu2+)/
reg1+reg2+emu1+emu2−
ii. F′ (reg1+reg2−emu1−emu2+)/
reg1+reg2+emu1+emu2−
c. What results do you predict for the two strains
(i and ii) if reg1 encodes the regulatory protein
and reg2 is the regulatory site?
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