Tumor suppressor genes and oncogenes are implicated in carcinogenesis. however, one can predict whether a gene potentially encodes for a protein that influences carcinogenesis by examining their mutational profile. you sequence the genome of 4 cancers and identify 3 genes of interest. which of the following genes has the best potential to an oncogene?

tumor 1 tumor 2 tumor 3 tumor 4
gene a s24f, n465t r33t t345s, g366r p367e, p368y
gene b s34r, f360i s34r v254i s34e, t67y
gene c s24f, i322e c255i, e344d s34e, p367e

a..gene a and c are potential oncogenes
b. gene b and c are potential oncogenes
c. gene b is a potential oncogene
d. none of the genes are potential oncogenes
e. all of the genes are potential oncogenes

Option A - Gene A and C are potential oncogenes

Explanation:

Oncogenes are genes that contribute to the conversion of a normal cell into a cancerous cell when mutated or expressed at high levels.

From the information provided:

Gene A S24F, N465T R33T T345S, G366R P367E, P368Y and

Gene C S24F, I322E C255I, E344D S34E, P367E

Both gene A and C have two similar sequences which represent potential sites of mutation

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.