Question

B. (10pts) Gene expression can be regulated in many ways. In the gene below, each letter represents a different mutation. Indicate which mutation would: (Use each letter only once.) trigger non-sense mediated decay increase transcript stability result in aberrant splicing reduce mRNA expression levels alter ADAR RNA editing promoter D — transcribed region intron A intron E exon- transcription factor binding sites exon spliced mRNA T 5'UTR CDS 3'UTR start codon stop codon C. (8pts) UAU encodes the amino acid Tyr. Give a point mutation would cause a conservative change a silent mutation a non-sense mutation a non-conservative change

Answer 1

1-A nonscence mediated decay causes degradation of transcript having premature stop codon. Hence The mutation in B region would cause the. occurence. of premature stop codon and will. lead to nonscence mediated. decay.

2- increased transcript stability can be because of themutation in C. region that codes for 3 prime region as, 3 prime regions contains regulatoru regions that post trancriptionaly maintain the stability of RNA.

3- Result in aberant splicing- Spilicing depends mostly on Exon-Intron junction sequences. Hence mutation in E region would affcet the spilcing.

4- Reduce in mRNA expression level- Mutation. in promoter region i.e D can cause reduction in Transcript as, it allows binding of essential tarsncription factor.mutation in the transcription factor binding sequenced may lead to reduced transcript level.

5- alter ADAR editing- ADAR is the Site-directed RNA editing. (A) should be the region that support Site-directed RNA editing, where it converts adenosine to (I) and can cause altered transcription.

UAU codes for tyrosine- a conservative chnage is the one which does not chnage the property of the amino acid. like tyrosine isa aromatic amino acid and phenyalanine as well so a UAU- UUU can cause a conservative chnage.

silent mutation is caused when a chnage in a codon codes for the same amino acid here a UAU ti UAC will cause a silent. mutation.

A non scence mutation causes a premature stop codon in the transcript so, a converstion of UAU to UAA(stop codon) will cause a nonscence muttaion.

a non-conservative change mutation is such that a codon change causes a different protein formation. i.e UAU codes for tyrosine but a chnage to UCU will chnage it to serine witha entirely different polar uncharged R group.