High impact information on B-H1

• Although deletion of BarH2 caused no appreciable morphological change in es organs, the simultaneous deletion of BarH1 and BarH2 led to a homeotic change in these organs with consequent conversion from campaniform-like sensilla to trichoid sensilla [1].
• Subtype determination of Drosophila embryonic external sensory organs by redundant homeo box genes BarH1 and BarH2 [1].
• Somatic recombination analysis indicated normal gene functions of the Bar region, including the BarH1 gene, to be required for normal eye morphogenesis [2].
• Both loci were found to share in common a different type of homeobox gene, which we call "BarH1." Polyptides encoded by D. melanogaster and D. ananassae BarH1 genes consist of 543 and 604 amino acids, respectively, with homeodomains identical in sequence except for one amino acid substitution [2].
• In Drosophila, BarH genes are necessary for the correct specification of R1/R6 eye photoreceptors [3].

Biological context of B-H1

• Barh1/h2 genes encode two related homeobox transcription factors (B-H1 and B-H2) previously shown to play essential roles in the formation and specification of the distal leg segments and in retinal neurogenesis [4].
• Induction and autoregulation of the anti-proneural gene Bar during retinal neurogenesis in Drosophila [5].
• This expression is regulated under the control of the ta5 enhancer activated by Bar. No activation of the ta5 enhancer, however, occurs in early third instar when considerable Bar is produced [6].
• In 1-3-day-old pupae, the level of the BarH1 transcript is higher [7].

Anatomical context of B-H1

• Dual Bar homeo box genes of Drosophila required in two photoreceptor cells, R1 and R6, and primary pigment cells for normal eye development [8].
• By immunostaining, we showed that BarH1 and BarH2 proteins are coexpressed in cells belonging to the central and peripheral nervous systems in embryos [1].
• Tarsus/pretarsus boundary formation requires at least two different Bar functions, early antagonistic interactions with a pretarsus-specific homeobox gene, aristaless, and the subsequent induction of Fas II expression in pretarsus cells abutting tarsal segment 5 [9].
• Expression of a medaka (Oryzias latipes) Bar homologue in the differentiating central nervous system and retina [10].

Associations of B-H1 with chemical compounds

• Drob-1 contains four conserved Bcl-2 homology domains (BH1, BH2, BH3, and BH4) and a C-terminal hydrophobic domain [11].
• Temporal regulation of late expression of Bar homeobox genes during Drosophila leg development by Spineless, a homolog of the mammalian dioxin receptor [6].

Physical interactions of B-H1

• The ta5 enhancer was comprised of a basal enhancer required for driving Bar expression and a negative regulatory motif serving as a binding site for the heterodimer of Spineless and Tango, homologs of the mammalian dioxin receptor and aryl hydrocarbon nuclear translocator, respectively [6].

Analytical, diagnostic and therapeutic context of B-H1

• By Northern blotting, considerably more BarH1 RNA was detected in the Bar mutant than in wild type [2].

References