Low levels of viral transcription ( basal transcription ) occur before expression of the virally encoded Tax protein ( Tax -mediated transcription ) .
low levels of viral transcription ( basal transcription ) occur before expression of the virally encoded tax protein ( tax -mediated transcription ) .
O O O B-other_name I-other_name O B-other_name I-other_name O O O O O O B-protein_molecule I-protein_molecule I-protein_molecule I-protein_molecule O B-protein_molecule O O O O