Gene silencing by modification of histones

Question 1

Process

Answer 1

1) Abf1, rap1, and ORC1 recruit sir 1,2,3,4 2)Sir 3/4 recruits sir 2 3) sir 2 deacetylates histones creating platform for sir3/4 4) extension of pattern

Question 2

sir 2

Answer 2

deacetylates histones creating platform for sir3/4 4) extension of pattern causing widespread deactivation; boundary elements contain the spreading.

Question 3

Silencing of HMRa and HMR alpha depends on…..

Answer 3

SIR (silencing information regulator) proteins; they establish and maintain heterochromatin.