Answer :
Final answer:
Dicer is the protein responsible for cleaving off the loop from a pre-miRNA, which is a crucial step in the maturation of miRNAs that regulate gene expression. Helper proteins are involved in mRNA processing, but not in pre-miRNA cleavage.
Explanation:
The protein that cleaves off the loop from a pre-miRNA is known as Dicer. Dicer is an essential enzyme in the process of microRNA (miRNA) maturation. During this process, Dicer recognizes the hairpin loop structure of the pre-miRNA and cuts it to produce a short double-stranded RNA molecule, which eventually leads to the formation of a mature miRNA. Mature miRNAs are important regulatory molecules that can control the expression of genes by binding to complementary sequences in messenger RNA (mRNA).
It is important to note that the role of helper proteins is quite different. They do not cleave pre-miRNA; instead, they assist in the processing of mRNA, such as removing non-coded areas from the precursor mRNA (pre-mRNA) to form a mature mRNA that codes for the final protein.
