Question

1) What are hnRNPs?. And how do they regulate gene expression. List a few examples of genes that are regulated by these.

2) To make a piece of mRNA, the RNA polymerase need to ‘know’ where to start and stop. Write about the signals and proteins involved in both initiating and terminating RNA polymerase activity in E. Coli.

Answer 1

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are complexes of RNA and protein present in the cell nucleus during gene transcription and subsequent post-transcriptional modification of the newly synthesized RNA .

hnRNA regulate Gene expression iduring transcription and RNA processing, which take place in the nucleus, and during protein translation, which takes place in the cytoplasm. Further regulation may occur through post-translational modifications of proteins.

Example:RNA editing.

RNA polymerase itself plays a role in the two principal mechanisms of initation termination that occur in E. coli. An additionalprotein, a initation-termination factor called Rho, is required in one mechanism but not the other.