Tag cns-enhancer-screen [9 articles]

Abstract

The enhancer trap approach utilizing transposons yields us information about gene functions and gene expression patterns. In the ascidian Ciona intestinalis, transposon-based transgenesis and insertional mutagenesis were achieved with a Tc1/mariner transposon Minos. We report development of a novel technique for enhancer trap in C. intestinalis. This technique uses remobilization of Minos in the Ciona genome. A Minos vector for enhancer trap was constructed and a tandem array insertion of the vector was introduced into the Ciona genome to create a ...

Abstract

The gene encoding DM20 emerged in cartilaginous fish, descending from a bilaterian ancestor of the M6 proteolipid gene family. Its proteolipid protein (PLP) isoform appeared in amphibians, contains an additional 35 amino acids, and, in the mammalian CNS, is the dominant myelin protein in which it confers an essential neuroprotective function. During development, the DM20 isoform is prominent in a number of tissues, and plp/DM20 transcripts are detected in multiple progenitor populations, including those that continue to express plp/DM20 as they ...

Abstract

The cis-regulatory regions of many developmental regulators and transcription factors are believed to be highly conserved in the genomes of vertebrate species, suggesting specific regulatory mechanisms for these gene classes. We functionally characterized five notochord enhancers, whose sequence is highly conserved, and systematically mutated two of them. Two subregions were identified to be essential for expression in the notochord of the zebrafish embryo. Synthetic enhancers containing the two essential regions in front of a TATA-box drive expression in the notochord while ...

Abstract

Silencers and enhancer-blockers (EBs) are cis-acting, negative regulatory elements (NREs) that control interactions between promoters and enhancers. Although relatively uncharacterized in terms of biological mechanisms, these elements are likely to be abundant in the genome. We developed an experimental strategy to identify silencers and EBs using transient transfection assays. A known insulator and EB from the chicken beta-globin locus, cHS4, served as a control element for these assays. We examined 47 sequences from a 1.8-Mb region of human chromosome 7 for ...

Abstract

Recent studies of the genome architecture of vertebrates have uncovered two unforeseen aspects of its organization. First, large regions of the genome, called gene deserts, are devoid of protein-coding sequences and have no obvious biological role. Second, comparative genomics has highlighted the existence of an array of highly conserved non-coding regions (HCNRs) in all vertebrates. Most surprisingly, these structural features are strongly associated with genes that have essential functions during development. Among these, the vertebrate Iroquois (Irx) genes stand out on ...

Abstract

Evolutionary sequence conservation is an accepted criterion to identify noncoding regulatory sequences. We have used a transposon-based transgenic assay in zebrafish to evaluate noncoding sequences at the zebrafish ret locus, conserved among teleosts, and at the human RET locus, conserved among mammals. Most teleost sequences directed ret-specific reporter gene expression, with many displaying overlapping regulatory control. The majority of human RET noncoding sequences also directed ret-specific expression in zebrafish. Thus, vast amounts of functional sequence information may exist that would not ...

Abstract

Bmp7 is expressed in numerous tissues throughout development and is required for morphogenesis of the eye, hindlimb and kidney. In this study we show that the majority if not all of the cis-regulatory sequence governing expression at these anatomical sites during development is present in approximately 20 kb surrounding exon 1. In eye, limb and kidney, multiple distinct enhancer elements drive Bmp7 expression within each organ. In the eye, the elements driving expression in the pigmented epithelium and iris are spatially ...

Abstract

Whole genome comparisons of distantly related species effectively predict biologically important sequences--core genes and cis-acting regulatory elements (REs)--but require experimentation to verify biological activity. To examine the efficacy of comparative genomics in identification of active REs from anonymous, non-coding (NC) sequences, we generated a novel alignment of the human and draft zebrafish genomes, and contrasted this set to existing human and fugu datasets. We tested the transcriptional regulatory potential of candidate sequences using two in vivo assays. Strict selection of non-genic ...

Abstract

In addition to protein coding sequence, the human genome contains a significant amount of regulatory DNA, the identification of which is proving somewhat recalcitrant to both in silico and functional methods. An approach that has been used with some success is comparative sequence analysis, whereby equivalent genomic regions from different organisms are compared in order to identify both similarities and differences. In general, similarities in sequence between highly divergent organisms imply functional constraint. We have used a whole-genome comparison between humans ...