Final answer:
SV40 T-antigen (NLS) is a protein produced by the SV40 virus that regulates transcription of genes essential to viral replication and viral particle formation. It also binds to p53, interfering with transcription of proteins regulated by p53, leading to uncontrolled cell division and the formation of cancerous tumors.
Step-by-step explanation:
SV40 T-antigen (NLS) is a protein produced by the SV40 virus. SV40 is a viral contaminant found in polio vaccines used in the 1960s. In infected cells, SV40 DNA enters the nucleus and integrates into the host cell genome. The SV40 T-antigen (NLS) regulates transcription of genes essential to viral replication and viral particle formation. It also binds to p53, a protein involved in regulating the cell cycle. This binding interferes with the transcription of proteins regulated by p53, leading to uncontrolled cell division and the formation of cancerous tumors.