Programming of gene expression by Polycomb group proteins

2008 ◽  
Vol 18 (5) ◽  
pp. 236-243 ◽  
Author(s):  
Claudia Köhler ◽  
Corina B.R. Villar
Keyword(s):  
Gene Expression ◽  
Polycomb Group ◽  
Polycomb Group Proteins

scholarly journals Molecular characterisation of the Polycomblike gene of Drosophila melanogaster, a trans-acting negative regulator of homeotic gene expression

Development ◽  
1994 ◽  
Vol 120 (9) ◽  
pp. 2629-2636 ◽  
Author(s):  
A. Lonie ◽  
R. D'Andrea ◽  
R. Paro ◽  
R. Saint
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Polycomb Group ◽  
Negative Regulator ◽  
Homeotic Gene ◽  
Homeotic Genes ◽  
Molecular Characterisation ◽  
Polycomb Group Proteins ◽  
Polycomb Group Genes ◽  
Homeotic Gene Expression

The Polycomblike gene of Drosophila melanogaster, a member of the Polycomb Group of genes, is required for the correct spatial expression of the homeotic genes of the Antennapaedia and Bithorax Complexes. Mutations in Polycomb Group genes result in ectopic homeotic gene expression, indicating that Polycomb Group proteins maintain the transcriptional repression of specific homeotic genes in specific tissues during development. We report here the isolation and molecular characterisation of the Polycomblike gene. The Polycomblike transcript encodes an 857 amino acid protein with no significant homology to other proteins. Antibodies raised against the product of this open reading frame were used to show that the Polycomblike protein is found in all nuclei during embryonic development. Antibody staining also revealed that the Polycomblike protein is found on larval salivary gland polytene chromosomes at about 100 specific loci, the same loci to which the Polycomb and polyhomeotic proteins, two other Polycomb Group proteins, are found. These data add further support for a model in which Polycomb Group proteins form multimeric protein complexes at specific chromosomal loci to repress transcription at those loci.

The Polycomb group in Caenorhabditis elegans and maternal control of germline development

Development ◽  
1998 ◽  
Vol 125 (13) ◽  
pp. 2469-2478 ◽  
Author(s):  
I. Korf ◽  
Y. Fan ◽  
S. Strome
Keyword(s):  
Gene Expression ◽  
Caenorhabditis Elegans ◽  
Polycomb Group ◽  
Polycomb Group Proteins ◽  
Polycomb Group Protein ◽  
Maternal Control ◽  
Germline Development ◽  
C Elegans ◽  
Polycomb Group Genes ◽  
Group Protein

Four Caenorhabditis elegans genes, mes-2, mes-3, mes-4 and mes-6, are essential for normal proliferation and viability of the germline. Mutations in these genes cause a maternal-effect sterile (i.e. mes) or grandchildless phenotype. We report that the mes-6 gene is in an unusual operon, the second example of this type of operon in C. elegans, and encodes the nematode homolog of Extra sex combs, a WD-40 protein in the Polycomb group in Drosophila. mes-2 encodes another Polycomb group protein (see paper by Holdeman, R., Nehrt, S. and Strome, S. (1998). Development 125, 2457–2467). Consistent with the known role of Polycomb group proteins in regulating gene expression, MES-6 is a nuclear protein. It is enriched in the germline of larvae and adults and is present in all nuclei of early embryos. Molecular epistasis results predict that the MES proteins, like Polycomb group proteins in Drosophila, function as a complex to regulate gene expression. Database searches reveal that there are considerably fewer Polycomb group genes in C. elegans than in Drosophila or vertebrates, and our studies suggest that their primary function is in controlling gene expression in the germline and ensuring the survival and proliferation of that tissue.

Function of the Polycomb protein is conserved in mice and flies

Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 2847-2852 ◽  
Author(s):  
J. Muller ◽  
S. Gaunt ◽  
P.A. Lawrence
Keyword(s):  
Gene Expression ◽  
Molecular Mechanism ◽  
Polycomb Group ◽  
Polycomb Group Proteins ◽  
Cell Fates ◽  
Cell Determination ◽  
Mouse Homologue ◽  
Polycomb Protein ◽  
Selector Genes ◽  
Transgenic Flies

A key aspect of determination--the acquisition and propagation of cell fates--is the initiation of patterns of selector gene expression and their maintenance in groups of cells as they divide and develop. In Drosophila, in those groups of cells where particular selector genes must remain inactive, it is the Polycomb-Group of genes that keep them silenced. Here we show that M33, a mouse homologue of the Drosophila Polycomb protein, can substitute for Polycomb in transgenic flies. Polycomb protein is thought to join with other Polycomb-Group proteins to build a complex that silences selector genes. Since members of this group of proteins have their homologues in mice, our results suggest that the molecular mechanism of cell determination is widely conserved.

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