Question

Direct recruitment of decapping enzymes by trans factors in the 3' UTR, and internal mRna cleavage by endoribonucleases exposing cut ends to it to 5' ? 3 and 3' ?5' exonucleolytic decay are examples of what type of decay?

Answer 1

The description refers to mRNA decay pathways which are critical in regulating gene expression by degrading mRNA molecules after the protective 5' cap and 3' poly-A tail have been removed or bypassed.

Step-by-step explanation:

The mRNA decay processes described involve mechanisms by which eukaryotic cells regulate the stability and turnover of mRNA molecules. These degradation pathways are essential for controlling gene expression and ensuring proper cellular function.

Direct recruitment of decapping enzymes by trans factors in the 3' untranslated region (UTR) is one such mechanism. This leads to the removal of the protective cap at the 5' end of the mRNA, rendering it susceptible to 5' to 3' exonucleolytic decay. Similarly, internal mRNA cleavage by endoribonucleases can leave mRNA vulnerable to both 5' to 3' and 3' to 5' exonucleolytic decay. The 5' cap and 3' poly-A tail are post-transcriptional modifications that protect mRNA from premature degradation; however, once these protective elements are removed or bypassed, decay mechanisms ensure removal of faulty or unneeded mRNA molecules from the cell.