Tat , a potent activator of HIV-1 gene expression , serves to greatly increase the rate of transcription directed by the viral promoter .
tat , a potent activator of hiv-1 gene expression , serves to greatly increase the rate of transcription directed by the viral promoter .
B-protein_molecule O O O O O B-virus O O O O O O O O O O B-other_name O O O B-DNA_domain_or_region I-DNA_domain_or_region O