Which one of the following acts as a linker histone?
Which one of the following acts as a linker histone?
Select an option to attempt
Correct Answer: Option A
Explanation
H1: The linker histone:Histone H1 is NOT part of the nucleosome core octamer. It functions as the linker histone:• Binds to the DNA that enters and exits the nucleosome (linker DNA, ~20–80 bp between nucleosomes)• Stabilises the nucleosome structure by locking the DNA in place• Essential for compaction of the 10 nm nucleosome 'beads-on-a-string' fibre into the 30 nm chromatin fibre• Each nucleosome has ONE H1 molecule (versus two copies each of H2A, H2B, H3, H4)Functions of core histones:• H3 and H4: form the tetramer that serves as the nucleosome 'reel'; most conserved histones• H2A and H2B: form two dimers that complete the octamerAnswer: H1 (Option 1).