Question

The following is true about Src genes and proteins.

a. v-src, is the first viral oncogene discovered in the Rous Sarcoma Virus (RSV). Deletion of v--src from the RSV genome resulted in a virus that could replicate in infected cells, but could no longer cause cellular transformation to a cancerous phenotype, while genetic insertion of the v-src gene into a normal retroviral genome resulted in a sarcoma--causing virus. These results show the necessity and sufficiency of the v-src gene for cell transformation.
b. The kinase activity of the c-Src protein can be activated by either deletion of the hosphorylated tyrosine at its C-terminal region (P-tyr-527), or displacement of intramolecular interactions of its SH2 and/or SH3 domains.
c. c-Src is the normal, non-receptor protein tyrosine kinase encoded in the mammalian genome that is a proto-oncogene.
d. All of the above

Answer 1

The v-src gene from Rous Sarcoma Virus is necessary and sufficient for cancerous cell transformation. The c-Src protein's activity is regulated by its C-terminal region and domain interactions, and c-Src functions as a proto-oncogene, highlighting the importance of these genes in oncogenic processes.

Step-by-step explanation:

The Src family of proteins encompasses several aspects of cellular regulation and has been implicated in the process of oncogenesis. Part (a) of the question highlights the foundational role of v-src, the viral proto-oncogene from Rous Sarcoma Virus, which is essential for the transformation of infected cells into a cancerous phenotype. This clearly signifies the necessity and sufficiency of v-src in cellular transformation.

Part (b) details how the kinase activity of the c-Src protein can be upregulated. This can occur through deletion or mutation of the regulatory phosphorylated tyrosine at the C-terminal region or through alteration in the SH2 and SH3 domain interactions, which are involved in intramolecular regulation.

Part (c) refers to c-Src as the normal cellular counterpart of the v-src gene, which is a non-receptor protein tyrosine kinase and functions as a proto-oncogene within the mammalian genome. The term proto-oncogene signifies that the gene has the potential to cause cancer when mutated or abnormally activated.

d. All of the above is the final answer, as each part reflects a separate yet accurate aspect of the Src genes and proteins, and their roles in signaling pathways that when dysregulated, can lead to cancer.