title: The highly conserved cardiogenic bHLH factor Hand is specifically expressed in circular visceral muscle progenitor cells and in all cell types of the dorsal vessel during Drosophila embryogenesis.
abstract: The highly conserved basic helix-loop-helix transcription factor Hand plays a crucial role in cardiogenesis, limb formation and other developmental processes of vertebrates. Humans, mice and other higher vertebrates have two related genes, dHand (also known as Hand2, Hed, Thing2) and eHand (also known as Hand1, Hxt, Thing1), whereas fish and Drosophila have only a single hand gene. We cloned Drosophila hand and studied the embryonic expression in detail by using various tissue-specific markers that allowed us to analyze the identity of hand-expressing cells. We found hand to be expressed in the entire heart, including all cardioblasts and pericardial cells, in the progenitors of the circular visceral muscles, the lymph gland and garland cells, and in a few cells in the CNS. The expression of Drosophila hand starts after the inductive activity of the early regulators in these tissues, e.g. Tinman and Bagpipe, suggesting a role of Hand in differentiation rather than in tissue determination. In many aspects the expression pattern of Drosophila hand resembles the patterns of its vertebrates orthologues, for instance in cardiac tissues. We assume that Hand proteins might play a highly conserved role throughout evolution.
authors.affiliation: Universität Marburg, Fachbereich Biologie-Entwicklungsbiologie, Karl von Frisch Strasse, 35032 Marburg, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Kölsch
authors.forename: Achim
authors.initials: A
authors.lastname: Paululat
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology*; D018257:Helix-Loop-Helix Motifs / Q000502:physiology*; D008969:Molecular Sequence Data; D009132:Muscles / Q000196:embryology*; D010802:Phylogeny; D013234:Stem Cells; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D029961:Zebrafish Proteins
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C475488:Hand protein, Drosophila; C410915:hand2 protein, zebrafish