scholarly journals Additional sex combs-like 1 belongs to the enhancer of trithorax and polycomb group and genetically interacts with Cbx2 in mice

2010 ◽  
Vol 337 (1) ◽  
pp. 9-15 ◽  
Author(s):  
C.L. Fisher ◽  
I. Lee ◽  
S. Bloyer ◽  
S. Bozza ◽  
J. Chevalier ◽  
...  
Genetics ◽  
1995 ◽  
Vol 140 (1) ◽  
pp. 231-243 ◽  
Author(s):  
M C Soto ◽  
T B Chou ◽  
W Bender

Abstract The genes of the Polycomb group (PcG) repress the genes of the bithorax and Antennapedia complexes, among others. To observe a null phenotype for a PcG gene, one must remove its maternal as well as zygotic contribution to the embryo. Five members of the PcG group are compared here: Enhancer of Polycomb [E(Pc)], Additional sex combs (Asx), Posterior sex combs (Psc), Suppressor of zeste 2 [Su (z) 2] and Polycomblike (Pcl). The yeast recombinase (FLP) system was used to induce mitotic recombination in the maternal germline. Mutant embryos were analyzed by staining with antibodies against six target genes of the PcG. The loss of the maternal component leads to enhanced homeotic phenotypes and to unique patterns of misexpression. E(Pc) and Su(z) 2 mutations had only subtle effects on the target genes, even when the maternal contributions were removed. Asx and Pcl mutants show derepression of the targets only in specific cell types. Psc shows unusual effects on two of the targets, Ultrabithorax and abdominal-A. These results show that the PcG genes do not act only in a common complex or pathway; they must have some independent functions.


Development ◽  
1998 ◽  
Vol 125 (7) ◽  
pp. 1207-1216 ◽  
Author(s):  
D.A. Sinclair ◽  
T.A. Milne ◽  
J.W. Hodgson ◽  
J. Shellard ◽  
C.A. Salinas ◽  
...  

The Additional sex combs (Asx) gene of Drosophila is a member of the Polycomb group of genes, which are required for maintenance of stable repression of homeotic and other loci. Asx is unusual among the Polycomb group because: (1) one Asx allele exhibits both anterior and posterior transformations; (2) Asx mutations enhance anterior transformations of trx mutations; (3) Asx mutations exhibit segmentation phenotypes in addition to homeotic phenotypes; (4) Asx is an Enhancer of position-effect variegation and (5) Asx displays tissue-specific derepression of target genes. Asx was cloned by transposon tagging and encodes a protein of 1668 amino acids containing an unusual cysteine cluster at the carboxy terminus. The protein is ubiquitously expressed during development. We show that Asx is required in the central nervous system to regulate Ultrabithorax. ASX binds to multiple sites on polytene chromosomes, 70% of which overlap those of Polycomb, polyhomeotic and Polycomblike, and 30% of which are unique. The differences in target site recognition may account for some of the differences in Asx phenotypes relative to other members of the Polycomb group.


Genetics ◽  
1992 ◽  
Vol 130 (4) ◽  
pp. 817-825 ◽  
Author(s):  
D A Sinclair ◽  
R B Campbell ◽  
F Nicholls ◽  
E Slade ◽  
H W Brock

Abstract Additional sex combs (Asx) is a member of the Polycomb group of genes, which are thought to be required for maintenance of chromatin structure. To better understand the function of Asx, we have isolated nine new alleles, each of which acts like a gain of function mutation. Asx is required for normal determination of segment identity. AsxP1 shows an unusual phenotype in that anterior and posterior homeotic transformations are seen in the same individuals, suggesting that AsxP1 might upset chromatin structure in a way that makes both activation and repression of homeotic genes more difficult. Analysis of embryonic and adult phenotypes of Asx alleles suggests that Asx is required zygotically for determination of segment number and polarity. The expression pattern of even-skipped is altered in Asx mutant embryos, suggesting that Asx is required for normal expression of this gene. We have transposon-tagged the Asx gene, and can thus begin molecular analysis of its function.


2011 ◽  
Vol 356 (1) ◽  
pp. 229
Author(s):  
Andrea L. Marion ◽  
Annie Lin ◽  
Mayur Patel ◽  
Heather Baskind ◽  
Qun-Tian Wang

2004 ◽  
Vol 323 (2) ◽  
pp. 523-533 ◽  
Author(s):  
Norihisa Shindo ◽  
Atsushi Sakai ◽  
Kouji Yamada ◽  
Toru Higashinakagawa

1994 ◽  
Vol 14 (3) ◽  
pp. 1721-1732 ◽  
Author(s):  
C A Bunker ◽  
R E Kingston

The Polycomb group (Pc-G) genes are essential for maintaining the proper spatially restricted expression pattern of the homeotic loci during Drosophila development. The Pc-G proteins appear to function at target loci to maintain a state of transcriptional repression. The murine oncogene bmi-1 has significant homology to the Pc-G gene Posterior sex combs (Psc) and a highly related gene, Suppressor two of zeste [Su(z)2]. We show here that the proteins encoded by bmi-1 and the Pc-G genes Polycomb (Pc) and Psc as well as Su(z)2 mediate repression in mammalian cells when targeted to a promoter by LexA in a cotransfection system. These fusion proteins repress activator function by as much as 30-fold, and the effect on different activation domains is distinct for each Pc-G protein. Repression is observed when the LexA fusion proteins are bound directly adjacent to activator binding sites and also when bound 1,700 bases from the promoter. These data demonstrate that the products of the Pc-G genes can significantly repress activator function on transiently introduced DNA. We suggest that this function contributes to the stable repression of targeted loci during development.


Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 1823-1838 ◽  
Author(s):  
Olivier Saget ◽  
Françoise Forquignon ◽  
Pedro Santamaria ◽  
Neel B Randsholt

Abstract We have analyzed the requirements for the multi sex combs (mxc) gene during development to gain further insight into the mechanisms and developmental processes that depend on the important trans-regulators forming the Polycomb group (PcG) in Drosophila melanogaster. mxc is allelic with the tumor suppressor locus lethal (1) malignant blood neoplasm (l(1)mbn). We show that the mxc product is dramatically needed in most tissues because its loss leads to cell death after a few divisions. mxc has also a strong maternal effect. We find that hypomorphic mxc mutations enhance other PcG gene mutant phenotypes and cause ectopic expression of homeotic genes, confirming that PcG products are cooperatively involved in repression of selector genes outside their normal expression domains. We also demonstrate that the mxc product is needed for imaginal head specification, through regulation of the ANT-C gene Deformed. Our analysis reveals that mxc is involved in the maternal control of early zygotic gap gene expression previously reported for some PcG genes and suggests that the mechanism of this early PcG function could be different from the PcG-mediated regulation of homeotic selector genes later in development. We discuss these data in view of the numerous functions of PcG genes during development.


2000 ◽  
Vol 20 (9) ◽  
pp. 3069-3078 ◽  
Author(s):  
Joyce Ng ◽  
Craig M. Hart ◽  
Kelly Morgan ◽  
Jeffrey A. Simon

ABSTRACT The extra sex combs (ESC) and Enhancer of zeste [E(Z)] proteins, members of the Polycomb group (PcG) of transcriptional repressors, interact directly and are coassociated in fly embryos. We report that these two proteins are components of a 600-kDa complex in embryos. Using gel filtration and affinity chromatography, we show that this complex is biochemically distinct from previously described complexes containing the PcG proteins Polyhomeotic, Polycomb, and Sex comb on midleg. In addition, we present evidence that ESC is phosphorylated in vivo and that this modified ESC is preferentially associated in the complex with E(Z). Modified ESC accumulates between 2 and 6 h of embryogenesis, which is the developmental time whenesc function is first required. We find that mutations inE(z) reduce the ratio of modified to unmodified ESC in vivo. We have also generated germ line transformants that express ESC proteins bearing site-directed mutations that disrupt ESC-E(Z) binding in vitro. These mutant ESC proteins fail to provideesc function, show reduced levels of modification in vivo, and are still assembled into complexes. Taken together, these results suggest that ESC phosphorylation normally occurs after assembly into ESC-E(Z) complexes and that it contributes to the function or regulation of these complexes. We discuss how biochemically separable ESC-E(Z) and PC-PH complexes might work together to provide PcG repression.


2008 ◽  
Vol 29 (2) ◽  
pp. 515-525 ◽  
Author(s):  
Stanley M. Lo ◽  
Nitin K. Ahuja ◽  
Nicole J. Francis

ABSTRACT The Drosophila melanogaster Polycomb group protein Posterior Sex Combs is a component of Polycomb repressive complex 1 and is central to Polycomb group-mediated silencing. A related Polycomb group gene, Suppressor 2 of zeste, is thought to be partially redundant in function. The two proteins share a small region of homology but also contain regions of unconserved sequences. Here we report a biochemical characterization of Suppressor 2 of zeste. Like Posterior Sex Combs, Suppressor 2 of zeste binds DNA, compacts chromatin, and inhibits chromatin remodeling. Interestingly, the regions of the two proteins responsible for these activities lack sequence homology. Suppressor 2 of zeste can also replace Posterior Sex Combs in a functional complex with other Polycomb group proteins, but unlike with their biochemical activities, complex formation is mediated by the region of Suppressor 2 of zeste that is homologous to that of Posterior Sex Combs. Our results establish Suppressor 2 of zeste as a functional homolog of Posterior Sex Combs and suggest that the two proteins operate via similar molecular mechanisms.


2016 ◽  
Vol 6 (10) ◽  
pp. a026526 ◽  
Author(s):  
Jean-Baptiste Micol ◽  
Omar Abdel-Wahab

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