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

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.

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Trans-regulation of thoracic homeotic selector genes of the Antennapedia and bithorax complexes by the trithorax group genes: absent, small, and homeotic discs 1 and 2

Mechanisms of Development ◽

10.1016/0925-4773(95)00430-0 ◽

1995 ◽

Vol 53 (1) ◽

pp. 123-139 ◽

Cited By ~ 36

Author(s):

Dennis LaJeunesse ◽

Allen Shearn

Keyword(s):

Trithorax Group ◽

Selector Genes ◽

Homeotic Selector Genes ◽

Trans Regulation ◽

Homeotic Selector

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The Tribolium homeotic gene Abdominal is homologous to abdominal-A of the Drosophila bithorax complex

Development ◽

10.1242/dev.117.1.233 ◽

1993 ◽

Vol 117 (1) ◽

pp. 233-243 ◽

Cited By ~ 8

Author(s):

J.J. Stuart ◽

S.J. Brown ◽

R.W. Beeman ◽

R.E. Denell

Keyword(s):

Molecular Analysis ◽

Tribolium Castaneum ◽

Functional Significance ◽

Homeotic Gene ◽

Bithorax Complex ◽

Developmental Genetic ◽

Selector Genes ◽

Homeotic Selector Genes ◽

Homeotic Selector

The Abdominal gene is a member of the single homeotic complex of the beetle, Tribolium castaneum. An integrated developmental genetic and molecular analysis shows that Abdominal is homologous to the abdominal-A gene of the bithorax complex of Drosophila. abdominal-A mutant embryos display strong homeotic transformations of the anterior abdomen (parasegments 7–9) to PS6, whereas developmental commitments in the posterior abdomen depend primarily on Abdominal-B. In beetle embryos lacking Abdominal function, parasegments throughout the abdomen are transformed to PS6. This observation demonstrates the general functional significance of parasegmental expression among insects and shows that the control of determinative decisions in the posterior abdomen by homeotic selector genes has undergone considerable evolutionary modification.

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Regulation of proboscipedia in Drosophila by Homeotic Selector Genes

Genetics ◽

10.1093/genetics/156.1.183 ◽

2000 ◽

Vol 156 (1) ◽

pp. 183-194

Author(s):

Douglas B Rusch ◽

Thomas C Kaufman

Keyword(s):

Expression Pattern ◽

Regulatory Element ◽

Polycomb Group ◽

Accumulation Pattern ◽

Cis Acting ◽

Polycomb Group Genes ◽

Gap Genes ◽

Combined Action ◽

Selector Genes

Abstract The gene proboscipedia (pb) is a member of the Antennapedia complex in Drosophila and is required for the proper specification of the adult mouthparts. In the embryo, pb expression serves no known function despite having an accumulation pattern in the mouthpart anlagen that is conserved across several insect orders. We have identified several of the genes necessary to generate this embryonic pattern of expression. These genes can be roughly split into three categories based on their time of action during development. First, prior to the expression of pb, the gap genes are required to specify the domains where pb may be expressed. Second, the initial expression pattern of pb is controlled by the combined action of the genes Deformed (Dfd), Sex combs reduced (Scr), cap'n'collar (cnc), and teashirt (tsh). Lastly, maintenance of this expression pattern later in development is dependent on the action of a subset of the Polycomb group genes. These interactions are mediated in part through a 500-bp regulatory element in the second intron of pb. We further show that Dfd protein binds in vitro to sequences found in this fragment. This is the first clear demonstration of autonomous positive cross-regulation of one Hox gene by another in Drosophila melanogaster and the binding of Dfd to a cis-acting regulatory element indicates that this control might be direct.

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Sequence of the Tribolium castaneum Homeotic Complex: The Region Corresponding to the Drosophila melanogaster Antennapedia Complex

Genetics ◽

10.1093/genetics/160.3.1067 ◽

2002 ◽

Vol 160 (3) ◽

pp. 1067-1074

Author(s):

Susan J Brown ◽

John P Fellers ◽

Teresa D Shippy ◽

Elizabeth A Richardson ◽

Mark Maxwell ◽

...

Keyword(s):

Tribolium Castaneum ◽

Hox Genes ◽

Transcription Unit ◽

Sex Combs Reduced ◽

Sex Combs ◽

Selector Genes ◽

Homeotic Selector Genes ◽

Encoding Genes ◽

Single Cluster ◽

Homeotic Selector

Abstract The homeotic selector genes of the red flour beetle, Tribolium castaneum, are located in a single cluster. We have sequenced the region containing the homeotic selector genes required for proper development of the head and anterior thorax, which is the counterpart of the ANTC in Drosophila. This 280-kb interval contains eight homeodomain-encoding genes, including single orthologs of the Drosophila genes labial, proboscipedia, Deformed, Sex combs reduced, fushi tarazu, and Antennapedia, as well as two orthologs of zerknüllt. These genes are all oriented in the same direction, as are the Hox genes of amphioxus, mice, and humans. Although each transcription unit is similar to its Drosophila counterpart in size, the Tribolium genes contain fewer introns (with the exception of the two zerknüllt genes), produce shorter mRNAs, and encode smaller proteins. Unlike the ANTC, this region of the Tribolium HOMC contains no additional genes.

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

Molecular and Cellular Biology ◽

10.1128/mcb.13.10.6357-6366.1993 ◽

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.

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Genetic analysis of the enhancer of zeste locus and its role in gene regulation in Drosophila melanogaster.

Genetics ◽

10.1093/genetics/126.1.185 ◽

1990 ◽

Vol 126 (1) ◽

pp. 185-199 ◽

Cited By ~ 9

Author(s):

R S Jones ◽

W M Gelbart

Keyword(s):

Gene Regulation ◽

Drosophila Melanogaster ◽

Ectopic Expression ◽

Polycomb Group ◽

Temperature Sensitive ◽

Loss Of Function ◽

Eye Color ◽

Polycomb Group Genes ◽

Enhancer Of Zeste ◽

Gene Complexes

Abstract The Enhancer of zeste [E(z)] locus of Drosophila melanogaster is implicated in multiple examples of gene regulation during development. First identified as dominant gain-of-function modifiers of the zeste1-white (z-w) interaction, mutant E(z) alleles also produce homeotic transformations. Reduction of E(z)+ activity leads to both suppression of the z-w interaction and ectopic expression of segment identity genes of the Antennapedia and bithorax gene complexes. This latter effect defines E(z) as a member of the Polycomb-group of genes. Analysis of E(z)S2, a temperature-sensitive E(z) allele, reveals that both maternally and zygotically produced E(z)+ activity is required to correctly regulate the segment identity genes during embryonic and imaginal development. As has been shown for other Polycomb-group genes, E(z)+ is required not to initiate the pattern of these genes, but rather to maintain their repressed state. We propose that the E(z) loss-of-function eye color and homeotic phenotypes may both be due to gene derepression, and that the E(z)+ product may be a general repressing factor required for both examples of negative gene regulation.

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Mammalian homologues of the Polycomb-group gene Enhancer of zeste mediate gene silencing in Drosophila heterochromatin and at S.cerevisiae telomeres

The EMBO Journal ◽

10.1093/emboj/16.11.3219 ◽

1997 ◽

Vol 16 (11) ◽

pp. 3219-3232 ◽

Cited By ~ 184

Author(s):

G. Laible

Keyword(s):

Gene Silencing ◽

Polycomb Group ◽

Enhancer Of Zeste ◽

Gene Enhancer ◽

Drosophila Heterochromatin ◽

Polycomb Group Gene

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Trans-Silencing by P Elements Inserted in Subtelomeric Heterochromatin Involves the Drosophila Polycomb Group Gene, Enhancer of zeste

Genetics ◽

10.1093/genetics/149.4.1839 ◽

1998 ◽

Vol 149 (4) ◽

pp. 1839-1855 ◽

Cited By ~ 10

Author(s):

Siobhan E Roche ◽

Donald C Rio

Keyword(s):

Transcriptional Repression ◽

Protein Product ◽

Polycomb Group ◽

P Element ◽

Subtelomeric Heterochromatin ◽

P Elements ◽

Enhancer Of Zeste ◽

Gene Enhancer ◽

Associated Sequences ◽

Polycomb Group Gene

AbstractDrosophila P-element transposition is regulated by a maternally inherited state known as P cytotype. An important aspect of P cytotype is transcriptional repression of the P-element promoter. P cytotype can also repress non-P-element promoters within P-element ends, suggesting that P cytotype repression might involve chromatin-based transcriptional silencing. To learn more about the role of chromatin in P cytotype repression, we have been studying the P strain Lk-P(1A). This strain contains two full-length P elements inserted in the heterochromatic telomere-associated sequences (TAS elements) at cytological location 1A. Mutations in the Polycomb group gene (Pc-G gene), Enhancer of zeste (E(z)), whose protein product binds at 1A, resulted in a loss of Lk-P(1A) cytotype control. E(z) mutations also affected the trans-silencing of heterologous promoters between P-element termini by P-element transgenes inserted in the TAS repeats. These data suggest that pairing interactions between P elements, resulting in exchange of chromatin structures, may be a mechanism for controlling the expression and activity of P elements.

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