cDNA cloning of a murine homologue of Drosophila single-minded, its mRNA expression in mouse development, and chromosome localization.
A combination of the RT-PCR method and subsequent screening of the cDNA library of mouse skeletal muscle with the cDNA isolated by RT-PCR used as a probe led to isolation of cDNAs encoding a polypeptide (mSim) with bHLH and PAS domains which show high similarity to the corresponding regions of Drosophila Sim, a master regulator in neurogenesis. Experiments using a GST-fusion protein demonstrated that mSim heterodimerizes with Arnt (Ah receptor nuclear translocator), even more efficiently than AhR (Ah receptor) does with Arnt. RNA blot analysis using RNAs from various tissues of mice indicated that mSim transcript is expressed in several limited tissues such as muscle, kidney and lung of adult animals. Distribution of mSim mRNA was always accompanied with that of Arnt. All the results suggest a regulatory role of mSim in partnership with Arnt. Chromosomal location of the mSim gene was determined by fluorescent in situ hybridization to be localized on the C3.3-C4 band of mouse chromosome 16 which is syntenic with the human chromosome 21q22 carrying the Down syndrome critical region, where a gene highly homologous to the Drosophila sim was localized. Whole mount in situ hybridization using a unique part of mSim cDNA sequence showed that mSim mRNA was expressed in the ventral diencephalon, branchial arches and limbs. These findings will provide an approach to the cause of the Down syndrome as well as the elucidation of the functional roles of mSim in animal development.
Ema
M
M
Department of Chemistry, Faculty of Science, Tohoku University, Sendai, Japan.
Suzuki
M
M
Morita
M
M
Hirose
K
K
Sogawa
K
K
Matsuda
Y
Y
Gotoh
O
O
Saijoh
Y
Y
Fujii
H
H
Hamada
H
H
Fujii-Kuriyama
Y
Y
D000367:Age Factors; D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018257:Helix-Loop-Helix Motifs; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D018336:Receptors, Aryl Hydrocarbon; D011994:Recombinant Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014157:Transcription Factors / Q000378:metabolism
D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D051792:Basic Helix-Loop-Helix Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D011994:Recombinant Proteins; D014157:Transcription Factors; C497397:Arnt protein, mouse; C089449:sim protein, Drosophila