Question

The functions which have been identified for the proteins encoded by cellular proto-oncogenes include all of the following except:

A. transcription factor

B. enzyme involved in DNA mismatch repair

C. growth factor receptor

D. growth factor

E. component of a signal transduction pathway

Answer 1

The Correct answer will be option 'B' i.e. enzyme involved in DNA Mismatch repair. Cellular proto-oncogenes are the normal genes involved in the cell growth. But point mutation, gene amplification or gene translocation can lead to the conversion of proto-oncogenes to oncogenes which may lead to tumor formation. The proteins encoded by cellular proto-oncogenes have several roles like growth factors and their receptors , signal transduction proteins ( ras protein), transcription factor (myc gene). But the enzyme involved in DNA Mismatch repair enzymes are the products of tumor suppressor genes. They can specifically called as care taker genes like mlh1 and msh2 which sense DNA base pair Mismatch.