Molecular characterization of HES-2, a mammalian helix-loop-helix factor structurally related to Drosophila hairy and Enhancer of split.
Drosophila hairy (h) plays a crucial role in early development as a pair-rule segmentation gene. h and its structurally related gene Enhancer of split [E(spl)] are also required for normal sensory neurogenesis in late development. To analyze the molecular mechanisms of mammalian development, we recently characterized three rat helix-loop-helix (HLH) factors that show structural homology to the Drosophila h and E(spl) gene products, and found that rat factors exhibit distinct spatiotemporal expression patterns and act as a negative regulator. Here, we report the molecular characterization of another member of this family, designated HES-2. Rat HES-2 protein has a basic HLH domain homologous to h and E(spl) as well as the carboxy-terminal Trp-Arg-Pro-Trp sequence conserved among this family. The HES-2 mRNA is present as early as embryonic day 9.5 and is detected in a variety of tissues of both embryos and adults. DNase-I-footprinting analyses indicate that HES-2 binds to all E box sequences (CANNTG) we tested as well as to the N-box sequences (CACNAG). Further studies of gel-mobility-shift assays show that HES-2 has a higher affinity for the E box than for the N box. Transient transfection analyses suggest that HES-2 decreases the transcription originating from the promoters containing either the E box or the N box. These results indicate that HES-2 acts as a negative regulator through interaction with both E-box and N-box sequences.
Ishibashi
M
M
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; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D004330:Drosophila; D029721:Drosophila Proteins; D007301:Insect Hormones / Q000737:chemistry / Q000235:genetics; D019476:Insect Proteins; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics; D014158:Transcription, Genetic
D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D007301:Insect Hormones; D019476:Insect Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; C082692:Hes2 protein, rat; C489235:hairy protein, Drosophila; C061841:hairy protein, insect