title: A leech homolog of twist: evidence for its inheritance as a maternal mRNA.
abstract: In the development of leeches such as Helobdella robusta, mesodermal and ectodermal fates segregate to cells DM and DNOPQ, respectively, at fourth cleavage. As one step in identifying genes that may act in mesoderm determination, we have cloned the H. robusta homolog to the Drosophila gene twist. This homolog, designated Hro-twi, exhibits high (> 90%) amino acid identity with other twist-class genes within its basic-helix loop-helix (b-HLH) DNA binding motif and dimerization domain. Like twist, Hro-twi contains CAX-rich stretches: three stretches 5' to the b-HLH and one located 3' of the b-HLH motif. RT-PCR analysis suggests that Hro-twi is present throughout development, beginning as a maternal transcript in the oocyte.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200, USA. sotoju@ziavms.enmu.edu
authors.forename: J G
authors.initials: JG
authors.lastname: Soto
authors.forename: B H
authors.initials: BH
authors.lastname: Nelson
authors.forename: D A
authors.initials: DA
authors.lastname: Weisblat
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005796:Genes / Q000235:genetics; D018257:Helix-Loop-Helix Motifs; D007865:Leeches / Q000196:embryology / Q000235:genetics*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D009865:Oocytes / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D051879:Twist-Related Protein 1
chemical_list: D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D051879:Twist-Related Protein 1