Please answer thoroughtly You are analyzing an unknown gene

Please answer thoroughtly.

You are analyzing an unknown gene that is expressed robustly under certain conditions. You have sequenced the gene and in the 5\' UTR of the mRNA you find the following sequence: 5\'-CGCCGCCGCCGCCGC-3\' Between this sequence and the start codon there is a stretch of nucleotides that could form a stem-loop that would prevent either transcription or translation (but you are not sure which).

A) What signal do you think this 5\' UTR is designed to sense?

B) Why might that signal occur? Name the molecules involved.

C) What might be the product of your unknown gene?

Solution

The 5 UTR [5 untranslated region], it also called as Leader Sequence /Leader RNA.

5 untranslated region of mRNA is directly on upstream from initiation codon. 5 untranslated region is important for regulation of the translation of Transcript by the different mechanism in the viruses & prokaryotes or eukaryotes. 5 UTR or it’s portion sometimes may translated into protein product. And This protein product can be regulate the translation of main coding sequence of mRNA.

In many organisms, 5 UTR is not translated completely, instead of that they forming a complex of secondary structure, so that they can regulate translation. 5 UTR are found to interact with the proteins that relating to the metabolism & proteins translated sequence within the 5’UTR. And 5’UTR region has also involved in the transcription regulation, for example-[ sex lethal genes in the Drosophila].another the Regulatory elements in 5 UTRs has been linked to the mRNA export.

these sequence: 5\'-CGCCGCCGCCGCCGC-3\' contain higher amount of [ G + C ]which have high M.W and high complimentary to form hairpin structure, because of these they could form a stem-loop that would prevent either transcription or translation.If stem loop form during the transcription and transcription abort, resulting no translation of m-RNA, there will be no protein product of unknown gene,

Another role of 5’UTR in protein translation –

prokaryotes,

in pk initiation of the translation occur when the IF-3 + 30S ribosomal subunit, that bind to Shine-Dalgarno sequence of 5 UTR. Than incorporate many different proteins, such as [50S ribosomal subunit] they allows for the translation begin. and regulates initiation of the translation.

In Eukaryotes play important role in

1.Preinitiation-complex -

regulation of the translation in the eukaryotes is more complex than the prokaryotes. Initially, eIF4F -complex is bind to 5 cap , than they recruit ribosomal complex to 5 UTR. than eIF4E and eIF4G both bind to the 5 UTR, that which limit the rate of translational initiation.

RNA-binding proteins sometimes serve to prevent the pre-initiation complex from forming. An example is regulation of the msl2 gene.

SXL protein attached to intron segment which located within 5UTR in primary transcript segment, which lead to removal of intron after the processing, and Sxl – protein can repress the translation of RNAs that not contain poly(A) tail, or 3 UTR.

Close loop regulation-important regulation of translation in that interaction between the 3 UTR and 5 UTR. And closed-loop structure are inhibits the translation.

conclusion

A) 5’ UTR is sense for regulation of the gene by interacting with different protein either in transcription or translation,

B) 5’UTR is important signal for m-RAN export from nucleus for translation. And there are many protein molecule involve in both prokaryotic or eukaryotic translation

C] Product of unknown gene may inhibit protein translation because it expressed robustly under adverse condition, for survival of organism under adverse condition because sequence: 5\'-CGCCGCCGCCGCCGC-3\' having high amount of G+C, form hair-pin loop to stop protein synthesis,