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Polycomb Group Gene (polycomb + group_gene)
Selected Abstractsoleed, a medaka Polycomb group gene, regulates ciliogenesis and left,right patterningGENES TO CELLS, Issue 12 2009Daisuke Arai Left-right (LR) patterning is an essential part of the animal body plan. Primary cilia are known to play a pivotal role in this process. In humans, genetic disorders of ciliogenesis cause serious congenital diseases. A comprehensive mechanism that regulates ciliogenesis has not been proposed so far. Here, we show that EED, a core member of the Polycomb group (PcG) genes and a presumed player in many epigenetic processes, is required for ciliogenesis and subsequent LR patterning in the medaka fish, Oryzias latipes. Moderate knockdown of oleed, a medaka homolog of EED, preferentially caused situs inversus. In the affected embryo, the cilia in Kupffer's vesicle showed various defects in their structure, position and motility. Furthermore, we demonstrated that oleed maintains the expression of Noto, which, in mice, regulates ciliogenesis and LR patterning. This study provides the first evidence for the involvement of epigenetic plasticity in LR patterning through ciliogenesis. [source] Differential expression of human Polycomb group proteins in various tissues and cell typesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue S36 2001Marco J. Gunster Abstract Polycomb group proteins are involved in the maintenance of cellular identity. As multimeric complexes they repress cell type-specific sets of target genes. One model predicts that the composition of Polycomb group complexes determines the specificity for their target genes. To study this hypothesis, we analyzed the expression of Polycomb group genes in various human tissues using Northern blotting and immunohistochemistry. We found that Polycomb group expression varies greatly among tissues and even among specific cell types within a particular tissue. Variations in mRNA expression ranged from expression of all analyzed Polycomb group genes in the heart and testis to no detectable Polycomb group expression at all in bone marrow. Furthermore, each Polycomb group gene was expressed in a different number of tissues. RING1 was expressed in practically all tissues, while HPH1 was expressed in only a few tissues. Also within one tissue the level of Polycomb group expression varied greatly. Cell type-specific Polycomb group expression patterns were observed in thyroid, pancreas, and kidney. Finally, in various developmental stages of fetal kidney, different Polycomb group expression patterns were observed. We conclude that Polycomb group expression can vary depending on the tissue, cell type, and development stage. Polycomb group complexes can only be composed of the Polycomb group proteins that are expressed. This implies that with cell type-specific Polycomb group expression patterns, cell type-specific Polycomb group complexes exist. The fact that there are cell type-specific Polycomb group targets and cell type-specific Polycomb group complexes fits well with the hypothesis that the composition of Polycomb group complexes may determine their target specificity. J. Cell. Biochem. Suppl. 36: 129,143, 2001. © 2001 Wiley-Liss, Inc. [source] | ||||||||||