A novel, tissue-specific, Drosophila homeobox gene.

Abstract

The homeobox gene family of Drosophila appears to control a variety of position‐specific patterning decisions during embryonic and imaginal development. Most of these patterning decisions determine groups of cells on the anterior‐posterior axis of the Drosophila germ band. We have isolated a novel homeobox gene from Drosophila, designated H2.0. H2.0 has the most diverged homeobox so far characterized in metazoa, and, in contrast to all previously isolated homeobox genes, H2.0 exhibits a tissue‐specific pattern of expression. The cells that accumulate transcripts for this novel gene correspond to the visceral musculature and its anlagen.

Novel murine homeo box gene on chromosome 1 expressed in specific hematopoietic lineages and during embryogenesis.

“…3) is interesting, because H2.0 is one of the few Drosophila homeo box genes exhibiting only tissue-specific expression, although the expression pattern of 1-12.0, visceral musculature, and its precursors (Barad et al 1988) is very different from that of Hlx. In any case, because H/x resembles 1-12.0 only in the homeo box and a few short additional regions {Figs.…”

“…It is expressed in cells of myeloid-macrophage lineage and at early stages of Blymphocyte development, as well as during embryogenesis. Its homeo box sequence is divergent from those of the known vertebrate genes but is closely related to that of the Drosophila H2.0 gene, one of the few fly genes that exhibit only tissue-specific expression (Barad et al 1988). To indicate this sequence relationship, the new gene will be denoted H/x, for H2.0-_like homeo box gene.…”

Molecular cloning of a diverged homeobox gene that is rapidly down-regulated during the G0/G1 transition in vascular smooth muscle cells.

“…This repeat encodes a stretch of glutamines and histidines and in the case of Gax encodes 18 residues, of which 12 are consecutive histidines. This motif is shared by other transcription factors, such as the zinc finger gene YY-1 (47,59), as well as by several homeobox genes, including H2.0, HB24, ERA-I (Hox-1.6), Dual bar, and Tes-I (6,22,32,38,50). Although the function of the polyhistidine-polyglutamine domain encoded by the CAX repeat is unknown, we note that several of the aforementioned homeodomain genes are important in regulating the proliferation and differentiation of the cells in which they are normally expressed.…”

Selector genes and the Cambrian radiation of Bilateria.

“…Increased constraint would not be expected in those organisms that are not serially constructed and presumably have not retained the simple ancestral regulatory hierarchy in development of selector gene differentiation of serial elements. The hypothesis of differential constraint tested against the fossil record in this paper can be further tested by examination ofthe distribution of selector genes in the genomes of arthropods.Evidence of homology in genes controlling body-plan development suggests a shared ancestry of genetic control of development in highly divergent bilaterian taxa, including insects and vertebrates (1)(2)(3)(4)(5)(6). In a phylogenetic context, these shared features of development derive from a common ancestor in the stem ofthe bilaterian clade and evolved before divergence of the higher metazoan groups we know today.…”

“…Evidence of homology in genes controlling body-plan development suggests a shared ancestry of genetic control of development in highly divergent bilaterian taxa, including insects and vertebrates (1)(2)(3)(4)(5)(6). In a phylogenetic context, these shared features of development derive from a common ancestor in the stem ofthe bilaterian clade and evolved before divergence of the higher metazoan groups we know today.…”