HUB1, a novel Krüppel type zinc finger protein, represses the human T cell leukemia virus type I long terminal repeat-mediated expression.
We have shown that human T-cell leukemia virus type I (HTLV-I) gene expression is negatively regulated by the U5 repressive element (U5RE) of its long terminal repeat (LTR). To isolate factors binding to U5RE, we screened a cDNA expression library by south-western blotting with a U5RE probe. Screening 2 x10(6) clones gave a positive clone with a 3.8 kb insert encoding a novel 671 residue polypeptide, named HTLV-I U5RE binding protein 1 (HUB1), with five zinc finger domains and a Krüppel-associated box like domain; HUB1 may be related to a repressor belonging to the Krüppel type zinc finger protein. A 4.0 kb mRNA for HUB1 is ubiquitously expressed among all human tissues tested. HUB1 recognizes the TCCACCCC sequence as a core motif and exerts a strong repressive effect on HTLV-I LTR-mediated expression. A new repressive domain, named HUB1 repressive (HUR) domain, was identified, rather than the Krüppel-associated box like domain. The N-terminal region upstream of HUR domain seemed to be also indispensable to the repression. Thus, we propose that HUB1 is a new type repressor and plays an important role in the HTLV-I U5-mediated repression.
Okumura
K
K
Shionogi Institute for Medical Science, 2-5-1 Mishima, Settsu, Osaka 566, Japan.
Sakaguchi
G
G
Naito
K
K
Tamura
T
T
Igarashi
H
H
D000595:Amino Acid Sequence; D018076:DNA, Complementary / Q000235:genetics; D015967:Gene Expression Regulation, Viral / Q000187:drug effects*; D015723:Gene Library; D006367:HeLa Cells; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D012097:Repressor Proteins