Molecular Genetic Analysis of Suppressor 2 of zeste Identifies Key Functional Domains

Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
Genetics (Impact Factor: 5.96). 07/2009; 182(4):999-1013. DOI: 10.1534/genetics.108.097360
Source: PubMed


The Su(z)2 complex contains Posterior sex combs (Psc) and Suppressor 2 of zeste [Su(z)2], two paralogous genes that likely arose by gene duplication. Psc encodes a Polycomb group protein that functions as a central component of the PRC1 complex, which maintains transcriptional repression of a wide array of genes. Although much is known about Psc, very little is known about Su(z)2, the analysis of which has been hampered by a dearth of alleles. We have generated new alleles of Su(z)2 and analyzed them at the genetic and molecular levels. Some of these alleles display negative complementation in that they cause lethality when heterozygous with the gain-of-function Su(z)2(1) allele but are hemizygous and, in some cases, homozygous viable. Interestingly, alleles of this class identify protein domains within Su(z)2 that are highly conserved in Psc and the mammalian Bmi-1 and Mel-18 proteins. We also find several domains of intrinsic disorder in the C-terminal regions of both Psc and Su(z)2 and suggest that these domains may contribute to the essential functions of both proteins.

4 Reads
  • Source
    • "Together, these genetic analyses suggest that Su(z)2 is a strong suppressor of dE2f1-dsRNA phenotypes. We then sought to extend this observation by examining additional Su(z)2 alleles described recently (Emmons et al. 2009). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The E2F transcription factors are important regulators of the cell cycle whose function is commonly misregulated in cancer. To identify novel regulators of E2F1 activity in vivo, we used Drosophila to conduct genetic screens. For this, we generated transgenic lines that allow the tissue-specific depletion of dE2F1 by RNAi. Expression of these transgenes using Gal4 drivers in the eyes and wings generated reliable and modifiable phenotypes. We then conducted genetic screens testing the capacity of Exelixis deficiencies to modify these E2F1-RNAi phenotypes. From these screens, we identified mutant alleles of Suppressor of zeste 2 [Su(z)2] and multiple Polycomb group genes as strong suppressors of the E2F1-RNA interference phenotypes. In validation of our genetic data, we find that depleting Su(z)2 in cultured Drosophila cells restores the cell-proliferation defects caused by reduction of dE2F1 by elevating the level of dE2f1. Furthermore, analyses of methylation status of histone H3 lysine 27 (H3K27me) from the published modENCODE data sets suggest that the genomic regions harboring dE2f1 gene and certain dE2f1 target genes display H3K27me during development and in several Drosophila cell lines. These in vivo observations suggest that the Polycomb group may regulate cell proliferation by repressing the transcription of dE2f1 and certain dE2F1 target genes. This mechanism may play an important role in coordinating cellular differentiation and proliferation during Drosophila development.
    G3-Genes Genomes Genetics 12/2012; 2(12):1651-60. DOI:10.1534/g3.112.004333 · 3.20 Impact Factor
  • Source
    • "). Natively unfolded regions occur in other chromatin architectural proteins, including the PcG proteins RYBP and GAGA factor, and have been proposed to play a role in the function of PSC and Su(z)2 (Agianian et al. 1999; Emmons et al. 2009; Lo et al. 2009; Neira et al. 2009). The linker histone regions required for chromatin compaction are intrinsically disordered in solution. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Polycomb group (PcG) proteins are required for the epigenetic maintenance of developmental genes in a silent state. Proteins in the Polycomb-repressive complex 1 (PRC1) class of the PcG are conserved from flies to humans and inhibit transcription. One hypothesis for PRC1 mechanism is that it compacts chromatin, based in part on electron microscopy experiments demonstrating that Drosophila PRC1 compacts nucleosomal arrays. We show that this function is conserved between Drosophila and mouse PRC1 complexes and requires a region with an overrepresentation of basic amino acids. While the active region is found in the Posterior Sex Combs (PSC) subunit in Drosophila, it is unexpectedly found in a different PRC1 subunit, a Polycomb homolog called M33, in mice. We provide experimental support for the general importance of a charged region by predicting the compacting capability of PcG proteins from species other than Drosophila and mice and by testing several of these proteins using solution assays and microscopy. We infer that the ability of PcG proteins to compact chromatin in vitro can be predicted by the presence of domains of high positive charge and that PRC1 components from a variety of species conserve this highly charged region. This supports the hypothesis that compaction is a key aspect of PcG function.
    Genes & development 10/2011; 25(20):2210-21. DOI:10.1101/gad.17288211 · 10.80 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Drosophila melanogaster was used to identify genes with a potential role in genetic regulation of purine biosynthesis. In this study we examine two dominant genetic modifiers of the essential gene Prat, which encodes amidophosphoribosyltransferase (EC We found that Mod(Prat:bw)3-1 enhances Prat expression only in female heads, whereas Mod(Prat:bw)3-5 suppresses Prat in all stages and tissues examined for both sexes. For Mod-3-5, gene expression microarrays were used to identify other genes that are affected by the modifier. Three mapping approaches were used to localize these modifiers. Deficiency and meiotic mapping showed that the complex lethal complementation group previously associated with Mod-3-1 and Mod-3-5 is actually due to shared second-site lethal mutations. Using male recombination mapping, Mod-3-1 was localized to a 21 kilobase region containing nine genes, and Mod-3-5 was localized to a 53 kilobase region containing eight genes.
    Genome 11/2009; 52(11):957-67. DOI:10.1139/g09-070 · 1.42 Impact Factor
Show more

Similar Publications


4 Reads
Available from