29. A gene producing red pigment was placed near centromeres of fission yeast and thus subjected to position effect variegation and produced white colonies, A screen for mutants that increased the red pigment production was undertaken. Which of the following genes, when mutated, is likely to produce this genotype?
(1) histone deacetylase
(2) Histone acetylase
(3) RNA polymerase II
(4) TATA binding factor
Summary:
Position effect variegation silences genes placed near heterochromatin regions such as centromeres. In fission yeast, mutation of histone deacetylase genes disrupts heterochromatin formation, leading to derepression of silenced genes and increased expression, as observed by enhanced red pigment production. This highlights the critical role of histone deacetylation in chromatin-mediated gene silencing.
Conclusion:
Mutation of histone deacetylase is most likely to increase red pigment production by relieving repression caused by PEV.
Correct answer:
(1) histone deacetylase
