Normal gene regulation in MAT locus Yeast: There are 3 regulatory protein in yeast mating control namely a1, alpha 1 & alpha 2. These 2 and alpha cells will have a opposite mating control genes.Thay both expose an suitable opposite attracting pheromones. a cells activate genes - Produce a factor and cell surface receptors - which binds with the alpha factor and provokes the signalling process and there by repress the same..This happens the same viceversa from alpha to a cells. alpha 1 - protein activator. alpha 2 - protein repressor. a1 - has no effect on its own, but forms complex with alpha 2 proteins and turns off different sets of genes. a2 expressed in haploid \"a\" cells - it does affect the regulation part bacause, this a2 protein shows no growth, and also mating/sporulation defects. It lacks to provoke the signalling of a factors and cell surface receptors, thereby fails to activate or repress the MAT locus gene regulation. So it\'s presence does not initiate any alteration in the gene regulation of MAT locus Solution Normal gene regulation in MAT locus Yeast: There are 3 regulatory protein in yeast mating control namely a1, alpha 1 & alpha 2. These 2 and alpha cells will have a opposite mating control genes.Thay both expose an suitable opposite attracting pheromones. a cells activate genes - Produce a factor and cell surface receptors - which binds with the alpha factor and provokes the signalling process and there by repress the same..This happens the same viceversa from alpha to a cells. alpha 1 - protein activator. alpha 2 - protein repressor. a1 - has no effect on its own, but forms complex with alpha 2 proteins and turns off different sets of genes. a2 expressed in haploid \"a\" cells - it does affect the regulation part bacause, this a2 protein shows no growth, and also mating/sporulation defects. It lacks to provoke the signalling of a factors and cell surface receptors, thereby fails to activate or repress the MAT locus gene regulation. So it\'s presence does not initiate any alteration in the gene regulation of MAT locus.

1. Normal gene regulation in MAT locus Yeast:
There are 3 regulatory protein in yeast mating control namely a1, alpha 1 & alpha 2.
These 2 and alpha cells will have a opposite mating control genes.Thay both expose an suitable
opposite attracting pheromones.
a cells activate genes - Produce a factor and cell surface receptors - which binds with the alpha
factor and provokes the signalling process and there by repress the same..This happens the same
viceversa from alpha to a cells.
alpha 1 - protein activator.
alpha 2 - protein repressor.
a1 - has no effect on its own, but forms complex with alpha 2 proteins and turns off different sets
of genes.
a2 expressed in haploid "a" cells - it does affect the regulation part bacause, this a2 protein
shows no growth, and also mating/sporulation defects.
It lacks to provoke the signalling of a factors and cell surface receptors, thereby fails to activate
or repress the MAT locus gene regulation.
So it's presence does not initiate any alteration in the gene regulation of MAT locus
Solution
Normal gene regulation in MAT locus Yeast:
There are 3 regulatory protein in yeast mating control namely a1, alpha 1 & alpha 2.
These 2 and alpha cells will have a opposite mating control genes.Thay both expose an suitable
opposite attracting pheromones.
a cells activate genes - Produce a factor and cell surface receptors - which binds with the alpha
factor and provokes the signalling process and there by repress the same..This happens the same
viceversa from alpha to a cells.
alpha 1 - protein activator.
alpha 2 - protein repressor.
a1 - has no effect on its own, but forms complex with alpha 2 proteins and turns off different sets
of genes.
a2 expressed in haploid "a" cells - it does affect the regulation part bacause, this a2 protein
shows no growth, and also mating/sporulation defects.
It lacks to provoke the signalling of a factors and cell surface receptors, thereby fails to activate
or repress the MAT locus gene regulation.
So it's presence does not initiate any alteration in the gene regulation of MAT locus