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Biomedical subjects

A Gossler

Publications and source records attributed to A Gossler.

5 recordsLinked to original sources
PubMed1992

The molecular and genetic analysis of mouse development.

This review describes some recent advances in the molecular-genetic analysis of mouse development. Reversed genetics and gene assignment have been used to isolate genes affected in developmental mutations. The establishment of a high-density molecular-genetic map promises to facilitate cloning of additional genes with developmental functions. Based on molecular, biochemical or other biological criteria many mouse genes that code for transcriptional regulators, growth-factor-like molecules and their receptors have been isolated. The role of these genes during development can be analysed in vivo after producing targeted mutations. Mutations can be generated by homologous recombination in the genome of embryonic stem cells and can then be introduced into the mouse germ line by means of germ-line chimaeras. Additional approaches employing stem cells to identify and mutate putative developmental genes are coming into use.

Animals↗
PubMed1992

Enhancer trap integrations in mouse embryonic stem cells give rise to staining patterns in chimaeric embryos with a high frequency and detect endogenous genes.

We have generated mouse embryonic stem cell lines that carry lacZ enhancer trap constructs integrated in their genome. Fifty-nine cell lines were analysed for lacZ expression in undifferentiated stem cells and at day 7.5, 8.5 and 12.5 of development in chimaeric embryos obtained after blastocyst injection. In 13 cell lines the lacZ reporter gene was expressed in undifferentiated stem cells ('blue', lines) as monitored by beta-galactosidase activity; 46 cell lines did not show detectable beta-galactosidase activity ('white', lines). In chimaeric embryos one-third of the analysed 59 embryonic stem cell lines gave rise to a variety of patterns. Six out of the 13 'blue' lines and 14 out of the 46 'white' lines showed spatially and temporally regulated patterns of beta-galactosidase expression and were additionally analysed on day 9.5. The majority of patterns showed staining exclusively or predominantly in structures of the developing nervous system, three patterns were observed only or predominantly in non-neuronal structures and five patterns were found exclusively in extraembryonic tissues. The analysis of DNA from cell lines that gave rise to staining patterns in chimaeric embryos showed that in 11 out of 15 cases simple integrations had occurred at a single site while in the remaining four cell lines multiple copies had integrated either at a single or at multiple sites. Flanking sequences from five reporter gene integrations have been cloned. At present, three integration sites have been analysed further and in all three cases we have identified transcribed sequences in the flanking DNA and isolated corresponding cDNA clones. The expression patterns of two of these genes were analysed by RNA in situ hybridisation. In both cases, expression of the endogenous genes was more widespread than the corresponding beta-galactosidase staining, suggesting that the reporter gene responded to only a subset of the regulatory elements of the endogenous gene. Our results demonstrate that enhancer trap integrations in embryonic stem cells can be used to efficiently identify transcriptional activation patterns during mouse embryogenesis and to isolate endogenous genes expressed in spatially and temporally regulated patterns.

Animals↗
PubMed1992

The mouse Enhancer trap locus 1 (Etl-1): a novel mammalian gene related to Drosophila and yeast transcriptional regulator genes.

A novel mouse gene, Enhancer trap locus 1 (Etl-1), was identified in close proximity to a lacZ enhancer trap integration in the mouse genome showing a specific beta-galactosidase staining pattern during development. In situ analysis revealed a widespread but not ubiquitous expression of Etl-1 throughout development with particularly high levels in the central nervous system and epithelial cells. The amino acid sequence of the Etl-1 protein deduced from the cDNA shows strong similarity, over a stretch of 500 amino acids, to the Drosophila brahma protein involved in the regulation of homeotic genes and to the yeast transcriptional activator protein SNF2/SWI2 as well as to the RAD54 protein and the recently described helicase-related yeast proteins STH1 and MOT1. Etl-1 is the first mammalian member of this group of proteins that are implicated in gene regulation and/or influencing chromatin structure. The homology to the regulatory proteins SNF2/SWI2 and brahma and the expression pattern during embryogenesis suggest that Etl-1 protein might be involved in gene regulating pathways during mouse development.

Amino Acid Sequence↗
PubMed1989

Mouse embryonic stem cells and reporter constructs to detect developmentally regulated genes.

A strategy was devised for identifying regions of the mouse genome that are transcriptionally active in a temporally and spatially restricted manner during development. The approach is based on the introduction into embryonic stem cells of two types of lacZ reporter constructs that can be activated by flanking mouse genomic sequences. Embryonic stem cells containing the lacZ constructs were used to produce chimaeric mice. Developmental regulation of lacZ expression occurred at a high frequency. Molecular cloning of the flanking endogenous genes and introduction of these potential insertional mutations into the mouse germ line should provide an efficient means of identifying and mutating novel genes important for the control of mammalian development.

Animals↗