Question

Please explain it well and with good answer please

It is essential for spliceosomes to remove introns precisely, that is, between the terminal nucleotide of an intron and the first nucleotide of an exon. To see why, suppose that the sequence at the normal junction in a pre-spliced mRNA between an intron and an exon is …UUAG GCUAACGG (Suppose further that a spliceosome occasionally miscleaves the pre-mRNA transcript between the C and U residues in the exon sequence to yield the following two splicing intermediates: UUAGGC UAACGG

What would be the consequence of this cleavage ?

Answer 1

When the exon is spliced in the positions where it is not suppsoed to, thus can lead to mutlpile issues in translation. Once of them if change of the frame work of the gene which in turn will give rise to the production of a completely different protein.

Here when the splicing happened between C and C it led to the production of two fragments, one is the intron and other one part of the exon. UAACGG should be part of th exon, here the cleavage between C and U led to the production of UAA as the first codon in the exon sequence.

UAA is a stop codon. Protein translation stops when ribosome recognises the stop codon. This will give rise to the production of truncated protein product which doesn't have any function.