97.MICRO RNA IS USEFUL IN
A.DNA SEQUENCING
B.GENE REGULATION
C.RNA SPLICING
D.
ANS:GENE REGULATION
The function of miRNAs appears to be in gene regulation. For that purpose, a miRNA is complementary to a part of one or more messenger RNAs (mRNAs). Animal miRNAs are usually complementary to a site in the 3' UTR whereas plant miRNAs are usually complementary to coding regions of mRNAs. Perfect or near perfect base pairing with the target RNA promotes cleavage of the RNA.This is the primary mode of plant miRNAs. In animals miRNAs more often have only partly the right sequence of nucleotides to bond with the target mRNA. The match-ups are imperfect. For partially complementary microRNAs to recognise their targets, nucleotides 2–7 of the miRNA (its 'seed region'[5][9]) still have to be perfectly complementary. Animal miRNAs inhibit protein translation of the target mRNA(this exists in plants as well but is less Common). MicroRNAs that are partially complementary to a target can also speed up deadenylation, causing mRNAs to be degraded sooner. While degradation of miRNA-targeted mRNA is well documented, whether or not translational repression is accomplished through mRNA degradation, translational inhibition, or a combination of the two is hotly debated. Recent work on miR-430 shows that translational repression is caused by the disruption of translation initiation, independent of mRNA deadenylation.
miRNAs occasionally also cause histone modification and DNA methylation of promoter sites, which affects the expression of target genes
A.DNA SEQUENCING
B.GENE REGULATION
C.RNA SPLICING
D.
ANS:GENE REGULATION
The function of miRNAs appears to be in gene regulation. For that purpose, a miRNA is complementary to a part of one or more messenger RNAs (mRNAs). Animal miRNAs are usually complementary to a site in the 3' UTR whereas plant miRNAs are usually complementary to coding regions of mRNAs. Perfect or near perfect base pairing with the target RNA promotes cleavage of the RNA.This is the primary mode of plant miRNAs. In animals miRNAs more often have only partly the right sequence of nucleotides to bond with the target mRNA. The match-ups are imperfect. For partially complementary microRNAs to recognise their targets, nucleotides 2–7 of the miRNA (its 'seed region'[5][9]) still have to be perfectly complementary. Animal miRNAs inhibit protein translation of the target mRNA(this exists in plants as well but is less Common). MicroRNAs that are partially complementary to a target can also speed up deadenylation, causing mRNAs to be degraded sooner. While degradation of miRNA-targeted mRNA is well documented, whether or not translational repression is accomplished through mRNA degradation, translational inhibition, or a combination of the two is hotly debated. Recent work on miR-430 shows that translational repression is caused by the disruption of translation initiation, independent of mRNA deadenylation.
miRNAs occasionally also cause histone modification and DNA methylation of promoter sites, which affects the expression of target genes
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