scholarly journals Hairless is a cofactor for Runt-dependent transcriptional regulation

2011 ◽  
Vol 22 (8) ◽  
pp. 1364-1374 ◽  
Author(s):  
Pegine B. Walrad ◽  
Saiyu Hang ◽  
J. Peter Gergen
Keyword(s):  
Transcriptional Regulation ◽  
Molecular Interactions ◽  
Target Gene ◽  
Transcriptional Regulator ◽  
Drosophila Embryo ◽  
Functional Requirements ◽  
Developmental Pathway ◽  
Downstream Target ◽  
Early Drosophila Embryo ◽  
Cellular Context

Runt is a vital transcriptional regulator in the developmental pathway responsible for segmentation in the Drosophila embryo. Runt activates or represses transcription in a manner that is dependent on both cellular context and the specific downstream target. Here we identify Hairless (H) as a Runt-interacting molecule that functions during segmentation. We find that H is important for maintenance of engrailed (en) repression as was previously demonstrated for Groucho (Gro), Rpd3, and CtBP. H also contributes to the Runt-dependent repression of sloppy-paired-1 (slp1), a role that is not shared with these other corepressors. We further find distinct roles for these different corepressors in the regulation of other Runt targets in the early Drosophila embryo. These findings, coupled with observations on the distinct functional requirements for Runt in regulating these several different targets, indicate that Runt-dependent regulation in the Drosophila blastoderm embryo relies on unique, target-gene-specific molecular interactions.

Regulation of a dpp target gene in the Drosophila embryo

Development ◽  
1997 ◽  
Vol 124 (2) ◽  
pp. 303-311 ◽  
Author(s):  
J. Rusch ◽  
M. Levine
Keyword(s):  
Target Gene ◽  
Fusion Gene ◽  
Drosophila Embryo ◽  
Specific Expression ◽  
Downstream Target ◽  
Embryonic Tissues ◽  
Posterior Midgut ◽  
Downstream Target Gene ◽  
Genetic Epistasis ◽  
Vp16 Fusion

In Drosophila, two TGF-beta growth factors, dpp and screw, function synergistically to subdivide the dorsal ectoderm into two embryonic tissues, the amnioserosa and dorsal epidermis. Previous studies have shown that peak dpp activity is required for the localized expression of zerknullt (zen), which encodes a homeodomain transcription factor. We present evidence that zen directly activates the amnioserosa-specific expression of a downstream target gene, Race (Related to angiotensin converting enzyme). A 533 bp enhancer from the Race promoter region is shown to mediate selective expression in the amnioserosa, as well as the anterior and posterior midgut rudiments. This enhancer contains three zen protein binding sites, and mutations in these sites virtually abolish the expression of an otherwise normal Race-lacZ fusion gene in the amnioserosa, but not in the gut. Genetic epistasis experiments suggest that zen is not the sole activator of Race, although a hyperactivated form of zen (a zen-VP16 fusion protein) can partially complement reduced levels of dpp activity. These results suggest that dpp regulates multiple transcription factors, which function synergistically to specify the amnioserosa.

Sloppy paired acts as the downstream target of wingless in the Drosophila CNS and interaction between sloppy paired and gooseberry inhibits sloppy paired during neurogenesis

Development ◽  
2000 ◽  
Vol 127 (3) ◽  
pp. 655-665 ◽  
Author(s):  
K.M. Bhat ◽  
E.H. van Beers ◽  
P. Bhat
Keyword(s):  
Target Gene ◽  
Ectopic Expression ◽  
Drosophila Embryo ◽  
Loss Of Function ◽  
Heterologous Promoter ◽  
Neuronal Precursor ◽  
Downstream Target ◽  
Wnt Proteins ◽  
Neuronal Lineage ◽  
Neuronal Precursor Cell

Wingless (Wg) and other Wnt proteins play a crucial role in a number of developmental decisions in a variety of organisms. In the ventral nerve cord of the Drosophila embryo, Wg is non-autonomously required for the formation and specification of a neuronal precursor cell, NB4-2. NB4-2 gives rise to a well-studied neuronal lineage, the RP2/sib lineage. While the various components of the Wg-signaling pathway are also required for generating NB4-2, the target gene(s) of this pathway in the signal-receiving cell is not known. In this paper, we show that sloppy paired 1 and sloppy paired 2 function as the downstream targets of the Wg signaling to generate the NB4-2 cell. Thus, while the loss-of-function mutations in wg and slp have the same NB4-2 formation and specification defects, these defects in wg mutants can be rescued by expressing slp genes from a heterologous promoter. That slp genes function downstream of the Wg signaling is also indicated by the result that expression of slp genes is lost from the neuroectoderm in wg mutants and that ectopic expression of wg induces ectopic expression of slp. Finally, previous results show that Gooseberry (Gsb) prevents Wg from specifying NB4-2 identity to the wg-expressing NB5-3. In this paper, we also show that gsb interacts with slp and prevents Slp from specifying NB4-2 identity. Overexpression of slp overcomes this antagonistic interaction and respecifies NB5-3 as NB4-2. This respecification, however, can be suppressed by a simultaneous overexpression of gsb at high levels. This mechanism appears to be responsible for specifying NB5-3 identity to a row 5 neuroblast and preventing Wg from specifying NB4-2 identity to that cell.

Drosophila-Raf Acts to Elaborate Dorsoventral Pattern in the Ectoderm of Developing Embryos

Genetics ◽  
2001 ◽  
Vol 159 (3) ◽  
pp. 1031-1044
Author(s):  
Kori Radke ◽  
Kimberly Johnson ◽  
Rong Guo ◽  
Anne Davidson ◽  
Linda Ambrosio
Keyword(s):  
Egf Receptor ◽  
Drosophila Embryo ◽  
Functional Requirements ◽  
Loss Of Function ◽  
Maternal Role ◽  
Partial Loss ◽  
Cell Fates ◽  
Regulatory Domains ◽  
Early Drosophila Embryo ◽  
Lateral Cell

Abstract In the early Drosophila embryo the activity of the EGF-receptor (Egfr) is required to instruct cells to adopt a ventral neuroectodermal fate. Using a gain-of-function mutation we showed that D-raf acts to transmit this and other late-acting embryonic Egfr signals. A novel role for D-raf was also identified in lateral cell development using partial loss-of-function D-raf mutations. Thus, we provide evidence that zygotic D-raf acts to specify cell fates in two distinct pathways that generate dorsoventral pattern within the ectoderm. These functional requirements for D-raf activity occur subsequent to its maternal role in organizing the anterioposterior axis. The consequences of eliminating key D-raf regulatory domains and specific serine residues in the transmission of Egfr and lateral epidermal signals were also addressed here.

scholarly journals Dosage-Sensitive Maternal Modifiers of the Drosophila Segmentation Gene runt

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 839-852
Author(s):  
Joseph B Duffy ◽  
James Wells ◽  
J Peter Gergen
Keyword(s):  
Transcriptional Regulation ◽  
Transcriptional Regulator ◽  
Drosophila Embryo ◽  
Over Expression ◽  
Spatial Regulation ◽  
Gap Genes ◽  
Pair Rule Gene ◽  
Pair Rule ◽  
Anterior Posterior

Abstract The protein encoded by the pair-rule gene runt functions as a transcriptional regulator during anterior-posterior patterning of the Drosophila embryo. Results of over-expression experiments as well as parallels drawn from the recent characterization of vertebrate homologues indicate that interactions with other proteins are likely to be central to the function of the Runt protein. To identify factors important for runt activity, we took advantage of an adult visible phenotype observed in animals heterozygous for runt mutations. Using a set of 126 different deficiency chromosomes we screened ~65% of the genome for genes that act as dose-sensitive maternal modifiers of runt. Eighteen deficiencies representing 12 putative loci were identified as maternally acting enhancers of runt haplo-insufficiency. Further characterization of two of these regions led to the identification of the interacting loci. Both of these loci affect the spatial regulation of runt transcription and appear genetically complex. Furthermore, the effects of one of these loci, M(1)1B, is indirect and mediated through effects on the transcriptional regulation of posterior gap genes.

The Regulation of Downstream Target Gene AP-2γ by Transcription Factor OCT-4

2013 ◽  
Vol 40 (1) ◽  
pp. 43
Author(s):  
Xiao-Meng ZHAO ◽  
Cheng WANG ◽  
Xiao-Feng LI ◽  
Xiao-Ting ZHANG ◽  
Xi-Zhi LIU ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Target Gene ◽  
Downstream Target ◽  
Downstream Target Gene

Aryl Hydrocarbon Receptor: Its Regulation and Roles in Transformation and Tumorigenesis

2019 ◽  
Vol 20 (6) ◽  
pp. 625-634 ◽  
Author(s):  
Xun Che ◽  
Wei Dai
Keyword(s):  
Target Gene ◽  
Tumor Development ◽  
Environmental Response ◽  
Carcinogenic Effect ◽  
Post Translational Modifications ◽  
Downstream Target ◽  
Aryl Hydrocarbon ◽  
Downstream Target Gene ◽  
Major Mediator

AhR is an environmental response gene that mediates cellular responses to a variety of xenobiotic compounds that frequently function as AhR ligands. Many AhR ligands are classified as carcinogens or pro-carcinogens. Thus, AhR itself acts as a major mediator of the carcinogenic effect of many xenobiotics in vivo. In this concise review, mechanisms by which AhR trans-activates downstream target gene expression, modulates immune responses, and mediates malignant transformation and tumor development are discussed. Moreover, activation of AhR by post-translational modifications and crosstalk with other transcription factors or signaling pathways are also summarized.

The Cytoskeleton of the Early Drosophila Embryo

1986 ◽  
Vol 1986 (Supplement 5) ◽  
pp. 311-328 ◽  
Author(s):  
R. M. WARN
Keyword(s):  
Drosophila Embryo ◽  
Early Drosophila Embryo
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