Chick NKx-2.3 represents a novel family member of vertebrate homologues to the Drosophila homeobox gene tinman: differential expression of cNKx-2.3 and cNKx-2.5 during heart and gut development.
NKx homeodomain proteins are members of a growing family of vertebrate transcription factors with strong homology to the NK genes in Drosophila. Here, we describe the cloning of cNKx-2.3 and cNKx-2.5 cDNAs and their expression during chick development. Both genes are expressed in the developing heart with distinct but overlapping spatio-temporal patterns. While cNKx-2.5 is activated in early precardiac mesoderm and continues to be uniformly expressed throughout the mature heart, expression of NKx-2.3 starts later in differentiated myocardial cells with regional differences compared to NKx-2.5. Additionally, both genes are expressed in adjacent domains of the developing mid- and hindgut mesoderm as well as in branchial arches. The highly conserved structure of cNKx-2.5 and its similar expression to mouse and Xenopus NKx-2.5 genes and to the Drosophila gene tinman argue that it constitutes the chick homologue of these genes. Different temporal and spatial activity of cNKx-2.3 in heart and gut as well as in a regionally restricted expression domain in the neural tube suggest that cNKx-2.3 is a member of the NK-2 gene family which may be involved in specifying mesodermally and ectodermally derived cell types in the embryo.
Buchberger
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A
Department of Cell and Molecular Biology, University of Braunschweig, Germany.
Pabst
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Brand
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Seidl
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K
Arnold
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HH
D000818:Animals; D030161:Avian Proteins; D001483:Base Sequence; D002642:Chick Embryo / Q000378:metabolism*; D002645:Chickens / Q000235:genetics* / Q000254:growth & development; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D006321:Heart / Q000196:embryology* / Q000254:growth & development; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000196:embryology*; D008648:Mesoderm / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics; D009206:Myocardium / Q000378:metabolism*; D009928:Organ Specificity; D016415:Sequence Alignment; D017385:Sequence Homology; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000235:genetics
D030161:Avian Proteins; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C103406:NKX2-3 protein, chicken; C092720:NKX2-5 protein, Xenopus; C095552:NKX2-5 protein, human; C484469:Nkx2-5 protein, mouse; D014157:Transcription Factors; D029867:Xenopus Proteins