Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00492 (hypoxanthine-guanine phosphoribosyltransferase)
 2,385 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been suggested that cell position regulates endodermal differentiation in mouse embryo inner cell masses and in aggregates of embryonal carcinoma (EC) cells. This hypothesis states that cells at the interface between the cell mass and blastocoel fluid or culture medium differentiate into endoderm, whereas internally located cells follow alternative developmental pathways. To test the cell position hypothesis, pluripotent PSA-1 cells were aggregated with hypoxanthine phosphoribosyltransferase-deficient, parietal-like, endodermal cells. The resulting aggregates consisted of cores of PSA-1 cells surrounded by endodermal cells. Autoradiography was used to distinguish between endodermal cells that were the products of EC cell differentiation and the exogenous endoderm. Alkaline phosphatase staining was used to distinguish EC cells from endodermal cells. As predicted by the cell position hypothesis, the PSA-1 EC cells, all of which were internally located, did not differentiate into endodermal cells. Nonspecific inhibition of differentiation did not account for the lack of PSA-1-derived endoderm since the PSA-1 cells in such aggregates did differentiate into columnar ectodermal-like cells. Similar experiments were also conducted with F9 cells. In this case, aggregation cultures contained retinoic acid to induce F9 cells to differentiate into visceral endoderm. In cultures containing F9 cells surrounded by parietal-like endodermal cells, no F9-derived endoderm was detected either autoradiographically or by assaying for alpha-fetoprotein production, a visceral endoderm marker. Thus, retinoic acid-induced endodermal differentiation was also regulated by cell position. Collectively, the above results provide strong evidence for the hypothesis that cell position regulates endodermal differentiation in aggregates of EC cells.
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PMID:Cell position regulates endodermal differentiation in embryonal carcinoma cell aggregates. 619 Jun 91

We describe here the construction and initial characterization of a 3-fold coverage genomic library of the human haploid genome that was prepared using the bacteriophage P1 cloning system. The cloned DNA inserts were produced by size fractionation of a Sau3AI partial digest of high molecular weight genomic DNA isolated from primary cells of human foreskin fibroblasts. The inserts were cloned into the pAd10sacBII vector and packaged in vitro into P1 phage. These were used to generate recombinant bacterial clones, each of which was picked robotically from an agar plate into a well of a 96-well microtiter dish, grown overnight, and stored at -70 degrees C. The resulting library, designated DMPC-HFF#1 series A, consists of approximately 130,000-140,000 recombinant clones that were stored in 1500 microtiter dishes. To screen the library, clones were combined in a pooling strategy and specific loci were identified by PCR analysis. On average, the library contains two or three different clones for each locus screened. To date we have identified a total of 17 clones containing the hypoxanthine-guanine phosphoribosyltransferase, human serum albumin-human alpha-fetoprotein, p53, cyclooxygenase I, human apurinic endonuclease, beta-polymerase, and DNA ligase I genes. The cloned inserts average 80 kb in size and range from 70 to 95 kb, with one 49-kb insert and one 62-kb insert.
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PMID:Preparation and screening of an arrayed human genomic library generated with the P1 cloning system. 814 66