scholarly journals The Drosophila ash1 Gene Product, Which Is Localized at Specific Sites on Polytene Chromosomes, Contains a SET Domain and a PHD Finger

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 913-928 ◽  
Author(s):  
Nicholas Tripoulas ◽  
Dennis LaJeunesse ◽  
John Gildea ◽  
Allen Shearn
Keyword(s):  
Amino Acids ◽  
Polytene Chromosomes ◽  
Protein Product ◽  
Polycomb Group ◽  
Transcriptional Level ◽  
Set Domain ◽  
Trithorax Group ◽  
Phd Finger ◽  
Polycomb Group Genes ◽  
The Stability

Abstract The determined state of Drosophila imaginal discs depends on stable patterns of homeotic gene expression. The stability of these patterns requires the function of the ash1 gene, a member of the trithorax group. The primary translation product of the 7.5-kb ash1 transcript is predicted to be a basic protein of 2144 amino acids. The ASHl protein contains a SET domain and a PHD finger. Both of these motifs are found in the products of some trithorax group and Polycomb group genes. We have determined the nucleotide sequence alterations in 10 ash1 mutant alleles and have examined their mutant phenotype. The best candidate for a null allele is ashl  22. The truncated protein product of this mutant allele is predicted to contain only 47 amino acids. The ASHl protein is localized on polytene chromosomes of larval salivary glands at >100 sites. The chromosomal localization of ASHl implies that it functions at the transcriptional level to maintain the expression pattern of homeotic selector genes.

The Drosophila Polycomb-group gene Enhancer of zeste contains a region with sequence similarity to trithorax

1993 ◽  
Vol 13 (10) ◽  
pp. 6357-6366
Author(s):  
R S Jones ◽  
W M Gelbart
Keyword(s):  
Amino Acids ◽  
Sequence Similarity ◽  
Protein Product ◽  
Polycomb Group ◽  
Acute Leukemias ◽  
Trithorax Group ◽  
Acid Protein ◽  
Enhancer Of Zeste ◽  
Gene Enhancer ◽  
Carboxy Terminal

As is typical of Polycomb-group loci, the Enhancer of zeste [E(z)] gene negatively regulates the segment identity genes of the Antennapedia (ANT-C) and Bithorax (BX-C) gene complexes. A second class of loci, collectively known as the trithorax group, plays an antagonistic role as positive regulators of the ANT-C and BX-C genes. Molecular analysis of the E(z) gene predicts a 760-amino-acid protein product. A region of 116 amino acids near the E(z) carboxy terminus is 41.2% identical (68.4% similar) with a carboxy-terminal region of the trithorax protein. This portion of the trithorax protein is part of a larger region previously shown to share extensive homology with a human protein (ALL-1/Hrx) that is implicated in acute leukemias. Over this same 116 amino acids, E(z) and ALL-1/Hrx are 43.9% identical (68.4% similar). Otherwise, E(z) is not significantly similar to any previously described proteins. As this region of sequence similarity is shared by two proteins with antagonistic functions, we suggest that it may comprise a domain that interacts with a common target, either nucleic acid or protein. Opposite effects on transcription might then be determined by other portions of the two proteins.

scholarly journals The Drosophila Polycomb-group gene Enhancer of zeste contains a region with sequence similarity to trithorax.

1993 ◽  
Vol 13 (10) ◽  
pp. 6357-6366 ◽  
Author(s):  
R S Jones ◽  
W M Gelbart
Keyword(s):  
Amino Acids ◽  
Sequence Similarity ◽  
Protein Product ◽  
Polycomb Group ◽  
Acute Leukemias ◽  
Trithorax Group ◽  
Acid Protein ◽  
Enhancer Of Zeste ◽  
Gene Enhancer ◽  
Carboxy Terminal

As is typical of Polycomb-group loci, the Enhancer of zeste [E(z)] gene negatively regulates the segment identity genes of the Antennapedia (ANT-C) and Bithorax (BX-C) gene complexes. A second class of loci, collectively known as the trithorax group, plays an antagonistic role as positive regulators of the ANT-C and BX-C genes. Molecular analysis of the E(z) gene predicts a 760-amino-acid protein product. A region of 116 amino acids near the E(z) carboxy terminus is 41.2% identical (68.4% similar) with a carboxy-terminal region of the trithorax protein. This portion of the trithorax protein is part of a larger region previously shown to share extensive homology with a human protein (ALL-1/Hrx) that is implicated in acute leukemias. Over this same 116 amino acids, E(z) and ALL-1/Hrx are 43.9% identical (68.4% similar). Otherwise, E(z) is not significantly similar to any previously described proteins. As this region of sequence similarity is shared by two proteins with antagonistic functions, we suggest that it may comprise a domain that interacts with a common target, either nucleic acid or protein. Opposite effects on transcription might then be determined by other portions of the two proteins.

The domino gene of Drosophila encodes novel members of the SWI2/SNF2 family of DNA-dependent ATPases, which contribute to the silencing of homeotic genes

Development ◽  
2001 ◽  
Vol 128 (8) ◽  
pp. 1429-1441 ◽  
Author(s):  
M.L. Ruhf ◽  
A. Braun ◽  
O. Papoulas ◽  
J.W. Tamkun ◽  
N. Randsholt ◽  
...  
Keyword(s):  
Polytene Chromosomes ◽  
Gene Mutations ◽  
Polycomb Group ◽  
Protein Isoforms ◽  
Homeotic Genes ◽  
Loss Of Function ◽  
Trithorax Group ◽  
A Subunit ◽  
The Common ◽  
Hematopoietic Disorders

The Drosophila domino gene has been isolated in a screen for mutations that cause hematopoietic disorders. Generation and analysis of loss-of-function domino alleles show that the phenotypes are typical for proliferation gene mutations. Clonal analysis demonstrates that domino is necessary for cell viability and proliferation, as well as for oogenesis. domino encodes two protein isoforms of 3202 and 2498 amino acids, which contain a common N-terminal region but divergent C termini. The common region includes a 500 amino acid DNA-dependent ATPase domain of the SWI2/SNF2 family of proteins, which function via interaction with chromatin. We show that, although domino alleles do not exhibit homeotic phenotypes by themselves, domino mutations enhance Polycomb group mutations and counteract Trithorax group effects. The Domino proteins are present in large complexes in embryo extracts, and one isoform binds to a number of discrete sites on larval polytene chromosomes. Altogether, the data lead us to propose that domino acts as a repressor by interfering with chromatin structure. This activity is likely to be performed as a subunit of a chromatin-remodeling complex.

E(z): a polycomb group gene or a trithorax group gene?

Development ◽  
1996 ◽  
Vol 122 (7) ◽  
pp. 2189-2197 ◽  
Author(s):  
D. LaJeunesse ◽  
A. Shearn
Keyword(s):  
Polycomb Group ◽  
Bithorax Complex ◽  
Trithorax Group ◽  
Polycomb Group Genes ◽  
Enhancer Of Zeste ◽  
Selector Genes ◽  
Homeotic Selector Genes ◽  
Polycomb Group Gene ◽  
Anterior Posterior ◽  
Homeotic Selector

The products of the Polycomb group of genes are cooperatively involved in repressing expression of homeotic selector genes outside of their appropriate anterior/posterior boundaries. Loss of maternal and/or zygotic function of Polycomb group genes results in the ectopic expression of both Antennapedia Complex and Bithorax Complex genes. The products of the trithorax group of genes are cooperatively involved in maintaining active expression of homeotic selector genes within their appropriate anterior/posterior boundaries. Loss of maternal and/or zygotic function of trithorax group genes results in reduced expression of both Antennapedia Complex and Bithorax Complex genes. Although Enhancer of zeste has been classified as a member of the Polycomb group, in this paper we show that Enhancer of zeste can also be classified as a member of the trithorax group. The requirement for Enhancer of zeste activity as either a trithorax group or Polycomb group gene depends on the homeotic selector gene locus as well as on spatial and temporal cues.

The enhancer of polycomb gene of Drosophila encodes a chromatin protein conserved in yeast and mammals

Development ◽  
1998 ◽  
Vol 125 (20) ◽  
pp. 4055-4066 ◽  
Author(s):  
K. Stankunas ◽  
J. Berger ◽  
C. Ruse ◽  
D.A. Sinclair ◽  
F. Randazzo ◽  
...  
Keyword(s):  
Position Effect ◽  
Polytene Chromosomes ◽  
Polycomb Group ◽  
Position Effect Variegation ◽  
Chromatin Protein ◽  
Heterochromatin Formation ◽  
C Elegans ◽  
Polycomb Group Genes ◽  
Effect Variegation ◽  
Or Gene

The Polycomb group of genes in Drosophila are homeotic switch gene regulators that maintain homeotic gene repression through a possible chromatin regulatory mechanism. The Enhancer of Polycomb (E(Pc)) gene of Drosophila is an unusual member of the Polycomb group. Most PcG genes have homeotic phenotypes and are required for repression of homeotic loci, but mutations in E(Pc) exhibit no homeotic transformations and have only a very weak effect on expression of Abd-B. However, mutations in E(Pc) are strong enhancers of mutations in many Polycomb group genes and are also strong suppressors of position-effect variegation, suggesting that E(Pc) may have a wider role in chromatin formation or gene regulation than other Polycomb group genes. E(Pc) was cloned by transposon tagging, and encodes a novel 2023 amino acid protein with regions enriched in glutamine, alanine and asparagine. E(Pc) is expressed ubiquitously in Drosophila embryogenesis. E(Pc) is a chromatin protein, binding to polytene chromosomes at about 100 sites, including the Antennapedia but not the Bithorax complex, 29% of which are shared with Polycomb-binding sites. Surprisingly, E(Pc) was not detected in the heterochromatic chromocenter. This result suggests that E(Pc) has a functional rather than structural role in heterochromatin formation and argues against the heterochromatin model for PcG function. Using homology cloning techniques, we identified a mouse homologue of E(Pc), termed Epc1, a yeast protein that we name EPL1, and as well as additional ESTs from Caenorhabditis elegans, mice and humans. Epc1 shares a long, highly conserved domain in its amino terminus with E(Pc) that is also conserved in yeast, C. elegans and humans. The occurrence of E(Pc) across such divergent species is unusual for both PcG proteins and for suppressors of position-effect variegation, and suggests that E(Pc) has an important role in the regulation of chromatin structure in eukaryotes.

scholarly journals The Transcriptional Coactivator SAYP Is a Trithorax Group Signature Subunit of the PBAP Chromatin Remodeling Complex

2008 ◽  
Vol 28 (9) ◽  
pp. 2920-2929 ◽  
Author(s):  
Gillian E. Chalkley ◽  
Yuri M. Moshkin ◽  
Karin Langenberg ◽  
Karel Bezstarosti ◽  
Andras Blastyak ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Polytene Chromosomes ◽  
Group Signature ◽  
Transcriptional Coactivator ◽  
Trithorax Group ◽  
Phd Finger ◽  
Gene Expression Control ◽  
Larval Salivary Gland ◽  
Eukaryotic Gene ◽  
Chromatin Remodeling Complexes

ABSTRACT SWI/SNF ATP-dependent chromatin remodeling complexes (remodelers) perform critical functions in eukaryotic gene expression control. BAP and PBAP are the fly representatives of the two evolutionarily conserved major subclasses of SWI/SNF remodelers. Both complexes share seven core subunits, including the Brahma ATPase, but differ in a few signature subunits; POLYBROMO and BAP170 specify PBAP, whereas OSA defines BAP. Here, we show that the transcriptional coactivator and PHD finger protein SAYP is a novel PBAP subunit. Biochemical analysis established that SAYP is tightly associated with PBAP but absent from BAP. SAYP, POLYBROMO, and BAP170 display an intimately overlapping distribution on larval salivary gland polytene chromosomes. Genome-wide expression analysis revealed that SAYP is critical for PBAP-dependent transcription. SAYP is required for normal development and interacts genetically with core- and PBAP-selective subunits. Genetic analysis suggested that, like BAP, PBAP also counteracts Polycomb silencing. SAYP appears to be a key architectural component required for the integrity and association of the PBAP-specific module. We conclude that SAYP is a signature subunit that plays a major role in the functional specificity of the PBAP holoenzyme.

scholarly journals Molecular Genetic Analysis of Drosophila ash2, a Member of the Trithorax Group Required for Imaginal Disc Pattern Formation

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 621-633 ◽  
Author(s):  
Amy L Adamson ◽  
Allen Shearn
Keyword(s):  
Pattern Formation ◽  
Fat Body ◽  
Polyclonal Antibodies ◽  
Molecular Genetic ◽  
Molecular Genetic Analysis ◽  
Polycomb Group ◽  
Trithorax Group ◽  
Phd Finger ◽  
Reading Frame ◽  
Active Transcription

Abstract The ash2 gene is a member of the trithorax group of genes whose products function to maintain active transcription of homeotic selector genes. Mutations in ash2 cause the homeotic transformations expected for a gene in this group but, in addition, cause a variety of pattern formation defects that are not necessarily expected. The ash2 gene is located in cytogenetic region 96A17–19 flanked by slowpoke and tolloid and is included in a cosmid that contains part of slowpoke. The ash2 transcript is 2.0 kb and is present throughout development. The ASH2 protein predicted from the nucleotide sequence of the open reading frame has a putative double zinc-finger domain, called a PHD finger, that is present not only in the products of other trithorax group genes such as TRX and MH1, but also in the product of a Polycomb group gene, PCL. Polyclonal antibodies directed against ASH2 detect the protein in imaginal discs and in the nuclei of salivary gland and fat body cells. On immunoblots these affinity-purified antibodies detect a 70-kDa protein in larvae and a 53-kDa protein in pupae.

Telomeric Associated Sequences of Drosophila Recruit Polycomb-Group Proteins in Vivo and Can Induce Pairing-Sensitive Repression

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 195-208 ◽  
Author(s):  
Antoine Boivin ◽  
Christelle Gally ◽  
Sophie Netter ◽  
Dominique Anxolabéhère ◽  
Stéphane Ronsseray
Keyword(s):  
Position Effect ◽  
Insertion Site ◽  
Polytene Chromosomes ◽  
Polycomb Group ◽  
Dependent Manner ◽  
Trithorax Group ◽  
Telomeric Silencing ◽  
Associated Sequences ◽  
Specific Factors

Abstract In Drosophila, relocation of a euchromatic gene near centromeric or telomeric heterochromatin often leads to its mosaic silencing. Nevertheless, modifiers of centromeric silencing do not affect telomeric silencing, suggesting that each location requires specific factors. Previous studies suggest that a subset of Polycomb-group (PcG) proteins could be responsible for telomeric silencing. Here, we present the effect on telomeric silencing of 50 mutant alleles of the PcG genes and of their counteracting trithorax-group genes. Several combinations of two mutated PcG genes impair telomeric silencing synergistically, revealing that some of these genes are required for telomeric silencing. In situ hybridization and immunostaining experiments on polytene chromosomes revealed a strict correlation between the presence of PcG proteins and that of heterochromatic telomeric associated sequences (TASs), suggesting that TASs and PcG complexes could be associated at telomeres. Furthermore, lines harboring a transgene containing an X-linked TAS subunit and the mini-white reporter gene can exhibit pairing-sensitive repression of the white gene in an orientation-dependent manner. Finally, an additional binding site for PcG proteins was detected at the insertion site of this type of transgene. Taken together, these results demonstrate that PcG proteins bind TASs in vivo and may be major players in Drosophila telomeric position effect (TPE).

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