Select the letter from the key which BEST fits each statement below, regarding eukaryotic post-transcriptional and translational control.

Eukaryotic Gene expression can be controlled post-transcriptionally and translationally

A critical mechanism in gene regulation within eukaryotic cells is the post-transcriptional, translational control gene expression. The modification, processing, and degrading of mRNA following transcription or before translation is called post-transcriptional. Translational control refers to the regulation and production of proteins from mRNA. Translational control and post-transcriptional control both play an important role in gene regulation. They allow for fine-tuning gene expression. Pre-transcriptional controls can be used to remove introns from premRNA and process 5′, 3′, and 3’ untranslated areas (UTRs). They also include adding a 3′ poly A tail and 5′ cap, as well as the degrading of mRNA molecules. All of these processes affect the stability, location and translation of mRNA. Komarova et. al. (2016) have shown that the rate at which mRNA is translated can be affected by the presence of UTRs. Additionally, specific elements found in the 3’ UTR could affect mRNA destruction rates (Wang, et. al., 2018,). At the start of protein synthesis, translational control can be achieved mainly through binding regulatory proteins to the mRNA. The context of the regulatory protein can determine whether it stimulates or suppresses translation. Specific microRNAs may regulate translation via binding to 3’UTRs. (Liu, et al. 2019, 2019).