Imagine a chromosome translocation event that brings a gene encoding a histone acetyl transferase enzyme from its original chromosomal location to a new one near heterochromatin. Which of the following scenarios is definitely NOT going to happen?

A. The gene gets silenced due to heterochromatin expansion, leading to the misregulation of gene expression for a number of critical genes.

B. The translocation event also brings along a chromatin barrier that can prevent heterochromatin expansion into the gene, and there is no phenotypic anomaly.

C. Since the gene encodes a histone acetyl transferase, it resists heterochromatin expansion by acetylating its own histones.

D. The level of the gene product decreases due to a position effect, leading to an imbalance in the chromatin state of the cell that results in the activation of programmed cell death.

Respuesta :

(C) option is correct

Explanation:

Since the gene encodes a histone acetyl transferase, it resists heterochromatin expansion by acetylating its own histones,this is the scenario which is not going to happen

  • In eukaryotic transcription initiation of a gene require change in chromatin structure(chromatin remodeling) because promoter and other regulatory elements of DNA exposed after removal of histone core
  • Chromatin remodeling can be induced by two separate mechanisms: Histone modification and histone displacement
  • By histone modification-it is an enzyme dependent but energy independent;includes acetylation,methylation and phosphorylation
  • Histone acetylation occurs on Lysine residue of H3 and H4 which is present in histone tail
  • Histone acetylation catalysed by an enzyme called as histone acetyl transferase(HAT)
  • Histone acetylation neutralises the positive charge of histone core and facilitate their dissociation
  • Histone acetylation favours gene expression
  • Histone deacetylation is the removal of acetyl group from histone tail which is catalysed by histone deacetylated enzyme and is always associated with gene repression