Explain how vitamin A regulates gene expression including sp

Explain how vitamin A regulates gene expression, including specific steps and the effect on mRNA and protein synthesis.

Solution

The active form of vitamin A, the retinoic acid plays a key role in gene expression as it acts as a ligand for the nuclear receptors. Retinoic acid binds to the retinoic acid receptors (RAR) that are associated with the retinoid-X-receptors (RXR). Dimerization of RAR and RXR occurs before binding to the DNA and only the dimeric form of these receptors is the active form. The can also form homodimers and heterodimers with the other receptor such as PPAR.

The four steps of involved in the gene regulation by vitamin A are,

1). Binding of the retinoid acid to the ligand binding site

2). Receptor dimerization with the retinoid-X-receptor (RXR)

3). Binding of heterodimer to the DNA binding site

4). Chromatin remodeling and transcriptional regulation.

Finally, the gene expression can be enhanced or decreased, which results in decreased or increased mRNA coding and thus, the protein synthesis.