DSpace Community:
https://hdl.handle.net/2440/47603
2024-03-28T21:53:15Z
2024-03-28T21:53:15Z
Receptor tyrosine kinase signaling regulates different modes of Groucho-dependent control of Dorsal
Hader, T.
Wainwright, D.
Shandala, T.
Saint, R.
Taubert, H.
Bronner, G.
Jackle, H.
https://hdl.handle.net/2440/49015
2023-11-20T18:46:55Z
2000-01-01T00:00:00Z
Title: Receptor tyrosine kinase signaling regulates different modes of Groucho-dependent control of Dorsal
Author: Hader, T.; Wainwright, D.; Shandala, T.; Saint, R.; Taubert, H.; Bronner, G.; Jackle, H.
Abstract: Transcriptional control of the Drosophila terminal gap gene huckebein (hkb) depends on Torso (Tor) receptor tyrosine kinase (RTK) signaling and the Rel/NFB homolog Dorsal (Dl) . Dl acts as an intrinsic transcriptional activator in the ventral region of the embryo, but under certain conditions, such as when it is associated with the non-DNA-binding co-repressor Groucho (Gro), it is converted into a repressor . Gro is recruited to the enhancer element in the vicinity of Dl by sequence-specific transcription factors such as Dead Ringer (Dri) . We examined the interplay between Dl, Gro and Dri on the hkb enhancer and show that when acting over a distance, Gro abolishes rather than converts Dl activator function. Reducing the distance between Dl- and Dri-binding sites, however, switches Dl into a Gro-dependent repressor that overrides activation of transcription. Both of the distance-dependent regulatory options of Gro - quenching and silencing of transcription- are inhibited by RTK signaling. These data describe a newly identified mode of function for Gro when acting in concert with Dl. RTK signaling provides a way of modulating Dl function by interfering either with Gro activity or with Dri-dependent recruitment of Gro to the enhancer.
2000-01-01T00:00:00Z
Phylogeny: The continuing classificatory conundrum of chaetognaths
Ball, Eldon E.
Miller, David J.
https://hdl.handle.net/2440/47889
2008-10-03T03:21:31Z
2006-01-01T00:00:00Z
Title: Phylogeny: The continuing classificatory conundrum of chaetognaths
Author: Ball, Eldon E.; Miller, David J.
Abstract: The phylogenetic conundrum posed by the Chaetognatha, a cryptic phylum consisting largely of planktonic predators, is the subject of two short papers in this issue of Current Biology. These analyses go some way towards defining the phylogenetic position of the chaetognaths, which possess features apparently spanning the protostome/deuterostome divide.
2006-01-01T00:00:00Z
Components of both major axial patterning systems of the Bilateria are differentially expressed along the primary axis of a 'radiate' animal, the anthozoan cnidarian Acropora millepora
de Jong, Danielle M.
Hislop, Nikki R.
Hayward, David C.
Reece-Hoyes, John S.
Pontynen, Patricia C.
Ball, Eldon E.
Miller, David J.
https://hdl.handle.net/2440/47888
2014-06-05T02:03:54Z
2006-01-01T00:00:00Z
Title: Components of both major axial patterning systems of the Bilateria are differentially expressed along the primary axis of a 'radiate' animal, the anthozoan cnidarian Acropora millepora
Author: de Jong, Danielle M.; Hislop, Nikki R.; Hayward, David C.; Reece-Hoyes, John S.; Pontynen, Patricia C.; Ball, Eldon E.; Miller, David J.
Abstract: Cnidarians are animals with a single (oral/aboral) overt body axis and with origins that nominally predate bilaterality. To better understand the evolution of axial patterning mechanisms, we characterized genes from the coral, Acropora millepora (Class Anthozoa) that are considered to be unambiguous markers of the bilaterian anterior/posterior and dorsal/ventral axes. Homologs of Otx/otd and Emx/ems, definitive anterior markers across the Bilateria, are expressed at opposite ends of the Acropora larva; otxA-Am initially around the blastopore and later preferentially toward the oral end in the ectoderm, and emx-Am predominantly in putative neurons in the aboral half of the planula larva, in a domain overlapping that of cnox-2Am, a Gsh/ind gene. The Acropora homologs of Pax-3/7, NKX2.1/vnd and Msx/msh are expressed in axially restricted and largely non-overlapping patterns in larval ectoderm. In Acropora, components of both the D/V and A/P patterning systems of bilateral animals are therefore expressed in regionally restricted patterns along the single overt body axis of the planula larva, and two 'anterior' markers are expressed at opposite ends of the axis. Thus, although some specific gene functions appear to be conserved between cnidarians and higher animals, no simple relationship exists between axial patterning systems in the two groups.
2006-01-01T00:00:00Z
Loss of Atrx affects trophoblast development and the pattern of x-inactivation in extraembryonic tissues
Garrick, David
Sharpe, Jackie A.
Arkell, Ruth
Dobbie, Lorraine
Smith, Andrew J. H.
Wood, William G.
Higgs, Douglas R.
Gibbons, Richard J.
https://hdl.handle.net/2440/47884
2008-10-09T01:15:30Z
2006-01-01T00:00:00Z
Title: Loss of Atrx affects trophoblast development and the pattern of x-inactivation in extraembryonic tissues
Author: Garrick, David; Sharpe, Jackie A.; Arkell, Ruth; Dobbie, Lorraine; Smith, Andrew J. H.; Wood, William G.; Higgs, Douglas R.; Gibbons, Richard J.
Abstract: ATRX is an X-encoded member of the SNF2 family of ATPase/helicase proteins thought to regulate gene expression by modifying chromatin at target loci. Mutations in ATRX provided the first example of a human genetic disease associated with defects in such proteins. To better understand the role of ATRX in development and the associated abnormalities in the ATR-X (alpha thalassemia mental retardation, X-linked) syndrome, we conditionally inactivated the homolog in mice, Atrx, at the 8- to 16-cell stage of development. The protein, Atrx, was ubiquitously expressed, and male embryos null for Atrx implanted and gastrulated normally but did not survive beyond 9.5 days postcoitus due to a defect in formation of the extraembryonic trophoblast, one of the first terminally differentiated lineages in the developing embryo. Carrier female mice that inherit a maternal null allele should be affected, since the paternal X chromosome is normally inactivated in extraembryonic tissues. Surprisingly, however, some carrier females established a normal placenta and appeared to escape the usual pattern of imprinted X-inactivation in these tissues. Together these findings demonstrate an unexpected, specific, and essential role for Atrx in the development of the murine trophoblast and present an example of escape from imprinted X chromosome inactivation.
Description: © 2006 Garrick et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
2006-01-01T00:00:00Z