please help! urgent

Question

Describe the structure and processing, and normal function of miRNAs and siRNAs. How can these RNAs be used to study the function of other genes (for example specific protein coding genes).

Answer 1

Bob,

 

Both microRNAs and siRNAs are non-coding RNAs involved in gene regulation. microRNAs are post-transcriptional modulators, they bind to 3' UTR of specific mRNAs (protein coding transcripts) and destabilize mRNA or inhibit its translation. A single microRNAs can bind to hundreds of different kinds of mRNAs,targets of microRNAs. 3' UTR of mRNAs have specific microRNA binding sites where binding occurs leading to either reduction or complete inhibition of translation. They function as bio-markers of  specific cancers and other conditions and also work as developmental switch in many model organisms.They have a stem-loop structure and are about 22 nucleotide long. They are processed by specific enzymes first in nucleus and then in cytoplasm. 

 

si RNAs are silencer RNAs that bind to transcripts and inhibit translation leading to gene silencing.

 

Please search sciencedirect.com for non-coding RNAs and read a review article. David Bartel has many excellent reviews on the subject.

 

Hope this helps.