Differentiation is an epigenetic process which is installed by changes of transcriptional programs over successive cellular divisions. A number of studies have reported the effects of biochemical modifications of chromatin (DNA and chromatin proteins) on the regulation of transcription. Although, these studies are able to explain how transcription of a given gene is regulated (toward activation...

differentiation is an epigenetic process which is installed by changes of transcriptional programs over successive cellular divisions. a number of studies have reported the effects of biochemical modifications of chromatin (dna and chromatin proteins) on the regulation of transcription. although, these studies are able to explain how transcription of a given gene is regulated (toward activation...

background: the aim of present study is to evaluate the effect of polyvinyl pyrrolidone (pvp) routinly used during icsi procedure on sperm membrane integrity, and sperm chromatin status. materials and methods: this study was carried out on 21 semen samples from the infertile men referring to isfahan fertility and infertility center. the processed semen samples were divided into two portions. on...

Centromeres are sites for assembly of the chromosomal structures that mediate faithful segregation at mitosis and meiosis. Plant and animal centromeres are typically located in megabase-sized arrays of tandem satellite repeats, making their precise mapping difficult. However, some rice centromeres are largely embedded in nonsatellite DNA, providing an excellent model to study centromere structu...

We have studied the ubiquitination and degradation patterns of the human securin/PTTG protein. We show that, in contrast to budding yeast pds1, securin degradation is catalyzed by both fzy (fizzy/cdc20) and fzr (fizzy-related/cdh1/hct1). Both fzy and fzr also induce the APC/C to ubiquitinate securin in vitro. Securin degradation is mediated by an RXXL destruction box and a KEN box, and is inhib...

In many eukaryotic species, gene order is not random. In humans, flies, and yeast, there is clustering of coexpressed genes that cannot be explained as a trivial consequence of tandem duplication. In the worm genome this is taken a step further with many genes being organized into operons. Here we analyze the relationship between gene location and expression in Caenorhabditis elegans and find e...