Judith Kassis, who heads the Section on Gene Expression, studies the mechanism of gene silencing by the Polycomb group genes (PcG) in Drosophila and the nature of DNA elements responsible for silencing (called Polycomb response elements or PREs). Polycomb group proteins are important epigenetic regulators whose activities are very important in embryonic stem cells and for differentiation. PREs are several hundred nucleotides in length and are made up of binding sites for numerous proteins. One focus of the group is to discover all of the DNA binding proteins that are required for PRE activity. They recently reported the discovery of a zinc-finger Sp1/KLF family member, Spps, that binds to PREs and is required for PRE activity. The role of Spps in recruitment of Polycomb protein complexes is currently being explored. The lab also studies the regulatory DNA of one of the target genes for Polycomb group proteins, engrailed. The goal of these experiments is to understand how PREs act to silence engrailed expression in some cells, while leaving it actively transcribed in others.
- Brown JL, Kassis JA. Spps, a Drosophila Sp1/KLF family member, binds to PREs and is required for PRE activity late in development. Development. 2010 Aug 1;137(15):2597-602.PMID: 20627963
- Cunningham MD, Brown JL, Kassis JA. Characterization of the polycomb group response elements of the Drosophila melanogaster invected Locus. Mol Cell Biol. 2010 Feb;30(3):820-8. Epub 2009 Nov 30.PMID: 19948883
- Kwon D, Mucci D, Langlais KK, Americo JL, DeVido SK, Cheng Y, Kassis JA. Enhancer-promoter communication at the Drosophila engrailed locus. Development. 2009 Sep;136(18):3067-75. Epub 2009 Aug 12.PMID: 19675130
- DeVido SK, Kwon D, Brown JL, Kassis JA. The role of Polycomb-group response elements in regulation of engrailed transcription in Drosophila. Development. 2008 Feb;135(4):669-76. Epub 2008 Jan 16.PMID: 18199580
- Müller J, Kassis JA.Polycomb response elements and targeting of Polycomb group proteins in Drosophila. Curr Opin Genet Dev. 2006 Oct;16(5):476-84. Epub 2006 Aug 17. Review.PMID: 16914306