Question

Complete elimination of a bacterial gene's Shine-Delgarno sequence Complete elimination of a gene's promoter A single base change in a bacterial gene's-35 TTGACA consensus sequence Complete elimination of the inverted repeat/hairpin loop structure and string • of uracils at the 3' untranslated region of a bacterial gene Complete elimination of the consensus sequence for 3 cleavage of a eukaryotic pre-mRNA Complete elimination of a splice site consensus sequence in a eukaryotic gene Abnormally long mRNA with the possibility of a short non-functional protein. 8. No effect on either transcription or translation No transcription: no translation Abnormally short pre-mRNA, with the possibbility of a short but functional protein E. Reduced rate of transcription Initiation Abnormally long mRNA may affect transcription and translation of neighboring F. downstream loci. No direct effect on transcription; mRNA half-life is reduced protein product levels are G.reduced H.No effect on transcription; little to no translation

Answer 1

1) Complete elimination of a bacterial gene's shine dalgarno sequence- No effect on transcription, little to no translation.

2) Complete elimination of a gene's promoter- No transcription, No translation

3) A single base change in a bacterial gene's -35 TTGACA consensus sequence- Reduced rate of transcription initiation

4) Complete elimination of the inverted repeat/hairpin loop structure and string of uracils at the 3' UTR of a bacterial gene- No direct effect on transcription, mRNA half life reduced, protein product levels are reduced.

5) Complete elimination of the consensus sequence for 3' cleavage of a eukaryotic pre-mRNA- Abnormally short pre-mRNA with the possibility of short and functional protein.

6) Complete elimination of a 5' splice site consensus sequence in a eukaryotic gene- Abnormally long mRNA and can affect transcription and translation of neighbouring downstream loci.

Explanation for the matches-

1) The shine dalgarno sequence is the sequence on the mRNA in prokaryotes which is complementary to the sequence on the small subunit of the ribosome.This helps the ribosome assembly onto the mRNA to begin transaltion.If this sequence is not there then the ribosomes do not know where to begin the process and hence there will be no translation occuring however transription is not affected.

2) The promoter is the region that is recognised by the RNA polymerase to begin transcription on the gene.This is the region that is upstream to the transcritpion start site. If the promoter is not present then the RNA polymerase cannot identify the region to bind on the DNA and cannot start transcription.If transcription does not occur then mRNA is not produced and hence transaltion also cannot occur.

3) The -35 consensus sequence is a conserved sequence in prokaryotes and is required to be precise for the efficient binding of the RNA polymerase. A change in single base will not affect transcription drastically but it will reduce the strong binding effect of the promoter due to which the rate of transcription of that particular gene will be reduced but not absent.

4) The 3' UTR region of a bacterial gene is necessary for the stability, export and translation efficiency of an mRNA.IT has no role to play in transcription but its removal can affect mRNA stability and reduced protein production.

5) when the 3' cleavage sequence is removed, polyadenylation a process of post transcriptional modification does not occur which means that the poly A tail is not formed and the mRNA has reduced shelf life. hence the pre mRNA is short but can be functional.

6) IF the 5' splice site sequence is removed then splicing (removal of introns and joining of exons) will not take place. Hence the mRNA will be long with a lot of exons(coding) and introns(non coding). and this can affect the regulation of other transcriptional and translational events.