A large-scale gene-trap screen for insertional mutations in developmentally regulated genes in mice.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 889-899 ◽  
Author(s):  
W Wurst ◽  
J Rossant ◽  
V Prideaux ◽  
M Kownacka ◽  
A Joyner ◽  
...  

Abstract We have used a gene-trap vector and mouse embryonic stem (ES) cells to screen for insertional mutations in genes developmentally regulated at 8.5 days of embryogenesis (dpc). From 38,730 cell lines with vector insertions, 393 clonal integrations had disrupted active transcription units, as assayed by beta-galactosidase reporter gene expression. From these lines, 290 clones were recovered and injected into blastocysts to assay for reporter gene expression in 8.5-dpc chimeric mouse embryos. Of these, 279 clones provided a sufficient number of chimeric embryos for analysis. Thirty-six (13%) showed restricted patterns of reporter-gene expression, 88 (32%) showed widespread expression and 155 (55%) failed to show detectable levels of expression. Further analysis showed that approximately one-third of the clones that did not express detectable levels of the reporter gene at 8.5 dpc displayed reporter gene activity at 12.5 dpc. Thus, a large proportion of the genes that are expressed in ES cells are either temporally or spatially regulated during embryogenesis. These results indicate that gene-trap mutageneses in embryonic stem cells provide an effective approach for isolating mutations in a large number of developmentally regulated genes.

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1216 ◽  
Author(s):  
Juliette M. Delhove ◽  
Rajvinder Karda ◽  
Lorna M. FitzPatrick ◽  
Suzanne M.K. Buckley ◽  
Simon N. Waddington ◽  
...  

Bioluminescence imaging enables noninvasive quantification of luciferase reporter gene expression in transgenic tissues of living rodents. Luciferase transgene expression can be regulated by endogenous gene promoters after targeted knock-in of the reporter gene, usually within the first intron of the gene. Even using CRISPR/Cas9 mediated genome editing this can be a time consuming and costly process. The generation of germline transgenic (GLT) rodents by targeted genomic integration of a gene expression cassette in embryonic stem (ES) cells is commonplace but results in the wastage of large numbers of animals during colony generation, back-crossing and maintenance. Using a synthetic/truncated promoter-driven luciferase gene to study promoter activity in a given tissue or organ of a GLT also often results in unwanted background luciferase activity during whole-body bioluminescent imaging as every cell contains the reporter. We have developed somatotransgenic bioimaging; a method to generate tissue-restricted transcription factor activated luciferase reporter (TFAR) cassettes in rodents that substantially reduces the number of animals required for experimentation. Bespoke designed TFARs are delivered to newborn pups using viral vectors targeted to specific organs by tissue-tropic pseudotypes. Retention and proliferation of TFARs is facilitated by stem/progenitor cell transduction and immune tolerance to luciferase due to the naïve neonatal immune system. We have successfully applied both lentiviral and adeno-associated virus (AAV) vectors in longitudinal rodent studies, targeting TFARs to the liver and brain during normal development and in well-established disease models. Development of somatotransgenic animals has broad applicability to non-invasively determine mechanistic insights into homeostatic and disease states and assess toxicology and efficacy testing. Somatotransgenic bioimaging technology is superior to current whole-body, light-emitting transgenic models as it reduces the numbers of animals used by generating only the required number of animals. It is also a refinement over current technologies given the ability to use conscious, unrestrained animals.


Blood ◽  
1998 ◽  
Vol 92 (12) ◽  
pp. 4622-4631 ◽  
Author(s):  
William L. Stanford ◽  
Georgina Caruana ◽  
Katherine A. Vallis ◽  
Maneesha Inamdar ◽  
Michihiro Hidaka ◽  
...  

Abstract We have developed a large-scale, expression-based gene trap strategy to perform genome-wide functional analysis of the murine hematopoietic and vascular systems. Using two different gene trap vectors, we have isolated embryonic stem (ES) cell clones containing lacZreporter gene insertions in genes expressed in blood island and vascular cells, muscle, stromal cells, and unknown cell types. Of 79 clones demonstrating specific expression patterns, 49% and 16% were preferentially expressed in blood islands and/or the vasculature, respectively. The majority of ES clones that expressedlacZ in blood islands also expressed lacZ upon differentiation into hematopoietic cells on OP9 stromal layers. Importantly, the in vivo expression of the lacZ fusion products accurately recapitulated the observed in vitro expression patterns. Expression and sequence analysis of representative clones suggest that this approach will be useful for identifying and mutating novel genes expressed in the developing hematopoietic and vascular systems.


Blood ◽  
1998 ◽  
Vol 92 (12) ◽  
pp. 4622-4631 ◽  
Author(s):  
William L. Stanford ◽  
Georgina Caruana ◽  
Katherine A. Vallis ◽  
Maneesha Inamdar ◽  
Michihiro Hidaka ◽  
...  

We have developed a large-scale, expression-based gene trap strategy to perform genome-wide functional analysis of the murine hematopoietic and vascular systems. Using two different gene trap vectors, we have isolated embryonic stem (ES) cell clones containing lacZreporter gene insertions in genes expressed in blood island and vascular cells, muscle, stromal cells, and unknown cell types. Of 79 clones demonstrating specific expression patterns, 49% and 16% were preferentially expressed in blood islands and/or the vasculature, respectively. The majority of ES clones that expressedlacZ in blood islands also expressed lacZ upon differentiation into hematopoietic cells on OP9 stromal layers. Importantly, the in vivo expression of the lacZ fusion products accurately recapitulated the observed in vitro expression patterns. Expression and sequence analysis of representative clones suggest that this approach will be useful for identifying and mutating novel genes expressed in the developing hematopoietic and vascular systems.


2013 ◽  
Vol 288 (29) ◽  
pp. 20776-20784 ◽  
Author(s):  
Feng-Tao Shi ◽  
Hyeung Kim ◽  
Weisi Lu ◽  
Quanyuan He ◽  
Dan Liu ◽  
...  

As a member of the Tet (Ten-eleven translocation) family proteins that can convert 5-methylcytosine (5mC) to 5-hydroxylmethylcytosine (5hmC), Tet1 has been implicated in regulating global DNA demethylation and gene expression. Tet1 is highly expressed in embryonic stem (ES) cells and appears primarily to repress developmental genes for maintaining pluripotency. To understand how Tet1 may regulate gene expression, we conducted large scale immunoprecipitation followed by mass spectrometry of endogenous Tet1 in mouse ES cells. We found that Tet1 could interact with multiple chromatin regulators, including Sin3A and NuRD complexes. In addition, we showed that Tet1 could also interact with the O-GlcNAc transferase (Ogt) and be O-GlcNAcylated. Depletion of Ogt led to reduced Tet1 and 5hmC levels on Tet1-target genes, whereas ectopic expression of wild-type but not enzymatically inactive Ogt increased Tet1 levels. Mutation of the putative O-GlcNAcylation site on Tet1 led to decreased O-GlcNAcylation and level of the Tet1 protein. Our results suggest that O-GlcNAcylation can positively regulate Tet1 protein concentration and indicate that Tet1-mediated 5hmC modification and target repression is controlled by Ogt.


Author(s):  
Wolfgang Wurst ◽  
Achim Gossler

Gene trap (GT) strategies in mouse embryonic stem (ES) cells are increasingly being used for detecting patterns of gene expression (1-4, isolating and mutating endogenous genes (5-7), and identifying targets of signalling molecules and transcription factors (3, 8-10). The general term gene trap refers to the random integration of a reporter gene construct (called entrapment vector) (11, 12) into the genome such that ‘productive’ integration events bring the reporter gene under the transcriptional regulation of an endogenous gene. In some cases this also simultaneously generates an insertional mutation. Entrapment vectors were originally developed in bacteria (13), and applied in Drosophila to identify novel developmental genes and/or regulatory sequences (14-17). Subsequently, a modified strategy was developed for mouse in which the reporter gene mRNA becomes fused to an endogenous transcript. Such ‘gene trap’ vectors were initially used primarily as a tool to discover genes involved in development (1, 2,18). In the last five years there has been a significant shift of GT approaches in mouse to much broader, large scale applications in the context of the analysis of mammalian genomes and ‘functional genomics’. Sequencing and physical mapping of both the human and mouse genomes is expected to be completed within the next five years. Already, a large number of mouse and human genes have been identified as expressed sequence tags (ESTs), and very likely the majority of genes will be discovered as ESTs shortly. This vast sequence information contrasts with a rather limited understanding of the in vivo functions of these genes. Whereas DNA sequence can provide some indication of the potential functions of these genes and their products, their physiological roles in the organism have to be determined by mutational analysis. Thus, the sequencing effort of the human genome project has to be complemented by efficient functional analyses of the identified genes. One potentially powerful complementation to the efforts of the human genome project would be a strategy whereby large scale random mutagenesis in mouse is combined with the rapid identification of the mutated genes (6,7,19, and German gene trap consortium, W. W. unpublished data).


Development ◽  
1996 ◽  
Vol 122 (7) ◽  
pp. 2271-2281 ◽  
Author(s):  
H. Weiler-Guettler ◽  
W.C. Aird ◽  
H. Rayburn ◽  
M. Husain ◽  
R.D. Rosenberg

Embryonic lethality of thrombomodulin-deficient mice has indicated an essential role for this regulator of blood coagulation in murine development. Here, the embryonic expression pattern of thrombomodulin was defined by surveying beta-galactosidase activity in a mouse strain in which the reporter gene was placed under the regulatory control of the endogenous thrombomodulin promoter via homologous recombination in embryonic stem cells. The murine trophoblast was identified as a previously unrecognized anatomical site where TM expression is conserved between humans and mice and may exert a critical function during postimplantation development. Targeted reporter gene expression in mesodermal precursors of the endothelial cell lineage defined thrombomodulin as an early marker of vascular differentiation. Analysis of the thrombomodulin promoter in differentiating ES cells and in transgenic mice provided evidence for a disparate and cell type-specific gene regulatory control mechanism in the parietal yolk sac. The thrombomodulin promoter as defined in this study will allow the targeting of gene expression to the parietal yolk sac of transgenic mice and the initiation of investigations into the role of parietal endoderm in placental function.


2018 ◽  
Author(s):  
Anastassiia Vertii ◽  
Jianhong Ou ◽  
Jun Yu ◽  
Aimin Yan ◽  
Hervé Pagès ◽  
...  

AbstractIn interphase eukaryotic cells, almost all heterochromatin is located adjacent to the nucleolus or to the nuclear lamina, thus defining Nucleolus-Associated Domains (NADs) and Lamina–Associated Domains (LADs), respectively. Here, we determined the first genome-scale map of murine NADs in mouse embryonic fibroblasts (MEFs) via deep sequencing of chromatin associated with purified nucleoli. We developed a Bioconductor package called NADfinder and demonstrated that it identifies NADs more accurately than other peak-calling tools, due to its critical feature of chromosome-level local baseline correction. We detected two distinct classes of NADs. Type I NADs associate frequently with both the nucleolar periphery and with the nuclear lamina, and generally display characteristics of constitutive heterochromatin, including late DNA replication, enrichment of H3K9me3 and little gene expression. In contrast, Type II NADs associate with nucleoli but do not overlap with LADs. Type II NADs tend to replicate earlier, display greater gene expression, and are more often enriched in H3K27me3 than Type I NADs. The nucleolar associations of both classes of NADs were confirmed via DNA-FISH, which also detected Type I but not Type II probes enriched at the nuclear lamina. Interestingly, Type II NADs are enriched in distinct gene classes, notably factors important for differentiation and development. In keeping with this, we observed that a Type II NAD is developmentally regulated, present in MEFs but not in undifferentiated embryonic stem (ES) cells.


2021 ◽  
Vol 14 (2) ◽  
pp. dmm047803
Author(s):  
Jens Hansen ◽  
Harald von Melchner ◽  
Wolfgang Wurst

ABSTRACTGene trapping is a high-throughput approach that has been used to introduce insertional mutations into the genome of mouse embryonic stem (ES) cells. It is performed with generic gene trap vectors that simultaneously mutate and report the expression of the endogenous gene at the site of insertion and provide a DNA sequence tag for the rapid identification of the disrupted gene. Large-scale international efforts assembled a gene trap library of 566,554 ES cell lines with single gene trap integrations distributed throughout the genome. Here, we re-investigated this unique library and identified mutations in 2202 non-coding RNA (ncRNA) genes, in addition to mutations in 12,078 distinct protein-coding genes. Moreover, we found certain types of gene trap vectors preferentially integrating into genes expressing specific long non-coding RNA (lncRNA) biotypes. Together with all other gene-trapped ES cell lines, lncRNA gene-trapped ES cell lines are readily available for functional in vitro and in vivo studies.


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