14. Out of the following matches of oncogenes with the proteins that each specifies, which one is incorrect?
    (1) erbA – thyroid hormone receptor.
    (2) erbB – epidermal growth factor receptor.
    (3) ras- guanine-nucleotide binding protein with GTPase activity.
    (4) fos – platelet-derived growth factor.

Final Answer

The oncogene-protein product match that is NOT correct among the options is:

(4) fos → platelet-derived growth factor

Explanation

• The fos oncogene encodes the nuclear protein c-Fos, a part of the AP-1 transcription factor complex. c-Fos is a DNA-binding transcription factor regulating gene expression related to cell proliferation, differentiation, and transformation. It is involved in signal transduction and acts as a regulator of cellular growth processes, not as a growth factor receptor or ligand.

• In contrast, platelet-derived growth factor (PDGF) is a distinct signaling protein involved in cell growth and angiogenesis but is not the protein product of the fos gene.

• Other matches are correct:

  • erbA → Thyroid hormone receptor

  • erbB → Epidermal Growth Factor receptor (EGFR)

  • ras → Guanine nucleotide-binding protein with GTPase activity

Thus, fos does not encode a growth factor but is a transcription factor contributing to oncogenic processes via gene regulation.​