Question

2) Why do most insertions of the viral genome occur in the exon 1 and intron 1 region?

3) If an insertion of the viral genome occur in the exon 2 or exon 3, does it convert the myc gene into an oncogene? If yes, how does it work? If not, why not?

Answer 1

2) Answer with explanation:- Exon 1 of myc gene is located in upstream region of this gene which does not take part in coding for amino acids of myc protein, but control the expression level of myc gene because having promotor and enhancer regions lie here. viral genomes show great attraction towards this region for integration and induces constitutive expression of myc gene. Thus converting it into oncogene by over expressing the myc protein which have role as transcriptional factor. 3' regions of myc intron 1 and Long Terminal Repeats in 5' Untranslated region of exon 1 could be the site of attraction for viral genome attraction. DNAase I hypersensitive site & AT rich regions both found to be the attaction site for viral genome integration in some studies.

3) answer with explanation:- If an insertion of viral genome occurs in the exon 2 and exon3, it does not convert myc gene into an oncogene. Both exons have coding sequence starting from start codon to stop codon for amino acids sequence of myc protein. any changes in these regions either by mutation or by viral genome integration can lead to inhibition of gene expression rather than overexpression that needed for oncogenicity.