Cytogenetic characterization of the 4BC region on the X chromosome of Drosophila melanogaster: Localization of the mei-9, norpA and omb genes

Abstract

Thirty genetic alterations, which involve the 4BC region of the Drosophila X chromosome, have been induced by ionizing radiation or by an endogenous mutator element. These mutations were recovered by screening for reversion of the dominant mutants Oce and Qd or for induction of the recessive mutants bi and rb. Among the 23 mutants generated by ionizing radiation, 20 have proven to be cytologically detectable chromosomal aberrations. Seven additional unique aberrations were generated in the Uc mutator strain. In total, 22 cytologically detectable deficiencies, 3 translocations, 1 inversion, 1 transposition, and 3 cytologically normal mutants have been recovered. Complementation analysis has permitted the cytogenetic localization of eight genes in the 4BC region. The mei-9 locus has been assigned to region 4B4-6, because this function is carried by Df(1)rb41 but not by Df(1)biD1. The norpA locus has been placed in the 4B6-C1 region based on its location between the distal breakpoints of Df(1)biD2 and Df(1)rb41. The genes lac, Qd, bi, and omb are localized to bands 4C5,6, rb to 4C6 and amb to 4C7,8. With one exception the complementation analysis has also permitted a determination of the linear sequence of these genes. This cytogenetic localization of these loci will facilitate the cloning and molecular analysis of genes controlling a key function in DNA repair and recombination (mei-9), and two fundamental neural functions (norpA and omb).

The role of the T-box gene optomotor-blind in patterning the Drosophila wing

“…omb 3198 is a lack-of-function allele produced by a point mutation that introduces a stop codon and generates a truncated protein (Poeck et al, 1993). omb bi (Banga et al, 1986) and omb-Gal4 (Lecuit et al, 1996) are two weak alleles. The fly stocks used were: vallecas (wild type), ap rK568 -lacZ (Cohen et al, 1992), brk X47 -lacZ (Campbell and Tomlinson, 1999), caps 02937 -lacZ (Shishido et al, 1998), Dad 1883 -lacZ (Tsuneizumi et al, 1997), dpp-lacZ (Blackman et al, 1991), mtv k00702 -lacZ (Funakoshi et al, 2001), omb P1 -lacZ (Sun et al, 1995), sal rN350 -lacZ G, sal 10.2S/C -lacZ (Kühnlein et al, 1997), tkv 16713 -lacZ (George and Terracol, 1997), trn s064117 -lacZ (Salzberg et al, 1997), vg QE -lacZ (Kim et al, 1996), dpp blk -Gal4 (Wilder and Perrimon, 1995), vg BE -Gal4 (Morimura et al, 1996), nub AC62 -Gal4 (gift of M. Calleja, CBM-CSIC Madrid, Spain), UAS-GFP (Davis et al, 1995), UAS-omb (Grimm and Pflugfelder, 1996), puc E69 -lacZ and UAS-puc (Martín-Blanco et al, 1998), UAS-p35 (Hay et al, 1994), Ac5C > y + > Gal4 (Ito et al, 1997) and N ts1 (Schallenberger and Mohler, 1978).…”

Abdominal Pigmentation Variation in Drosophila Polymorpha: Geographic Variation in the Trait, and Underlying Phylogeography

“…Relevant to this study, omb is also involved in patterning the adult abdomen (Kopp and Duncan 1997). The locus is complex, but a class of alleles, the Quadroon (Qd) alleles, are known to only affect the abdomen (Banga et al 1986;Pflugfelder et al 1990;Kopp and Duncan 1997). Specifically, the Qd 1 mutation in the omb gene of D. melanogaster produces overly pigmented males (females are not as dramatically overpigmented, and therefore were not used here).…”

The lethal(1)optomotor-blind gene of Drosophila melanogaster is a major organizer of optic lobe development: isolation and characterization of the gene.

“…Subsequent mutational screens for the neuroanatomical defect among the progeny of ethyl methanesulfonate-mutagenized flies by a mass histological procedure (6) yielded additional but only lethal alleles. A number of lethal mutations with one chromosome break at the omb locus have been obtained also by other groups (7,8). The cloning of the locus and the mapping of omb breakpoints indicated a minimum size of 80 kilobases (kb) for the omb gene (9).…”