Molecular characterization of a rat negative regulator with a basic helix-loop-helix structure predominantly expressed in the developing nervous system.
We report here the cDNA cloning and characterization of a rat basic helix-loop-helix (HLH) factor, designated HES-5. This factor has a distant sequence homology to Drosophila hairy and Enhancer-of-split proteins, both of which are required for normal neurogenesis. DNase I footprinting analyses show that HES-5 binds to the sequence CACNAG (called N box), a recognition sequence of Enhancer-of-split proteins. Although HES-5 does not bind to the sequence CANNTG (called E box) recognized by other HLH factors, it attenuates the binding of E47, an HLH activator, to E box by forming a hetero-oligomer. In cotransfection analyses using NIH 3T3 cells, HES-5 significantly represses transcription originating from the promoter containing the N box sequences. Furthermore, HES-5 also partially inhibits the E47-induced expression from the promoter containing E boxes. Northern blot, RNase protection, and in situ hybridization analyses demonstrate that the HES-5 mRNA is specifically expressed in the nervous system. Prominent expression is observed in the ventricular zones of the embryonal brain vesicles and the outer nuclear layer of the neural retina. These results suggest that the negative regulator HES-5 may play an important role in neural development.
Akazawa
C
C
Institute for Immunology, Kyoto University Faculty of Medicine, Japan.
Sasai
Y
Y
Nakanishi
S
S
Kageyama
R
R
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D015152:Blotting, Northern; D001921:Brain / Q000196:embryology / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014162:Transfection
D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C489685:Hes5 protein, mouse; C489686:Hes5 protein, rat