...Olivia R. A. Tidswell; Matthew A. Benton; Michael Akam ABSTRACT The neuroblast timer genes hunchback , Krüppel , nubbin and castor are expressed in temporal sequence in neural stem cells, and in corresponding spatial sequence along the Drosophila blastoderm. As canonical gap genes, hunchback...

...Alexander C. Cerny; Gregor Bucher; Reinhard Schröder; Martin Klingler During Drosophila segmentation, gap genes function as short-range gradients that determine the boundaries of pair-rule stripes. A classical example is Drosophila Krüppel (Dm'Kr) which is expressed in the middle of the syncytial...

... germ insect, Gryllus bimaculatus (Gb). Here, we have focused on its hunchback ortholog(Gb ' hb), because Drosophila hb functions as a gap gene during anterior segmentation, referred as a canonical function. Gb'hb is expressed in a gap pattern during the early stages of embryogenesis, and later...

... formative mechanisms may be operating in blastoderm-derived and germband-derived segments. In Drosophila , the gap gene Krüppel is required for proper formation of the central portion of the embryo. This domain of Krüppel activity in Drosophila corresponds to a region that in short and intermediate...

... that formation of these segments may rely on a different mechanism. Nevertheless, the expression and function of many segmentation genes seem conserved between Tribolium and Drosophila . We have cloned the Tribolium ortholog of the abdominal gap gene giant . As in Drosophila , Tribolium giant is expressed in two...

... derived transcription factors, including repressors encoded by gap genes such as Krüppel, knirps, giant and the mesoderm-specific snail . The mechanism of repression by gap transcription factors is not well understood at a molecular level. Initial characterization of these transcription factors suggests...

... 1998 © 1998 by Company of Biologists 1998 orthodenticle OTX1 OTX2 Gap gene Brain development Genetic rescue Evolution The cephalic gap gene orthodenticle (otd) is required for head development and segmental patterning in Drosophila . At early blastoderm stages...

...Jonathan S. Margolis; Mark L. Borowsky; EirÍkur SteingrÍmsson; Chung Wha Shim; Judith A. Lengyel; James W. Posakony ABSTRACT The gap gene hunchback (hb) is required for the formation and segmentation of two regions of the Drosophila embryo, a broad anterior domain and a narrow posterior domain...

... morphogen bicoid . In support of this, expression of synthetic reporter gene constructs containing oligomerized binding sites for the Bicoid protein was reduced in hs/runt embryos. Finally, genetic experiments demonstrated that regulation of gap gene expression by runt is a normal component...

... and posterior regions of the embryo by maternal organizers such as bed and osk . Since Kr has no maternal counterpart, the organization of the central segment pattern elements of the embryo may depend exclusively on zygotic activity provided by the gap gene Kr . The expression pattern of Kr in bcd/osk...