Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.5.1.3 (dihydrofolate reductase)
 5,819 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Progeny from one intra- and two inter-specific backcrosses between divergent strains of mice were typed to map multiple markers in relation to two pigment mutations on mouse chromosome 13, beige (bg) and pearl (pe). Both recessive mutants on a C57BL/6J background were crossed separately with laboratory strain PAC (M. domesticus) and the partially inbred M. musculus stock PWK. The intra- and inter-specific F1 hybrids were backcrossed to the C57BL/6J parental strain and DNA was prepared from progeny. Restriction fragment length polymorphisms were used to follow the segregation of alleles in the backcross offspring at loci identified with molecular probes. The linkage analysis defines the association between the bg and pe loci and the loci for the T-cell receptor gamma-chain gene (Tcrg), the spermatocyte specific histone gene (Hist1), the prolactin gene (Prl), the Friend murine leukaemia virus integration site 1 (Fim-1), the murine Hanukuh Factor gene (Muhf/Ctla-3) and the dihydrofolate reductase gene (Dhfr). This data confirms results of prior chromosomal mapping studies utilizing bg as an anchor locus, and provides previously unreported information defining the localization of the prolactin gene on mouse chromosome 13. The relationship of multiple loci in relation to pe is similarly defined. These results may help facilitate localization of the genes responsible for two human syndromes homologous with bg and pe, Chediak-Higashi syndrome and Hermansky-Pudlak syndrome.
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PMID:Linkage of loci associated with two pigment mutations on mouse chromosome 13. 168 16

Genetic transformation of Leishmania has relied upon two exogenous selectable markers, neo and hyg, encoding resistance to G418 and hygromycin B respectively. There is a need for multiple independent selectable markers, since Leishmania is diploid and experimental sexual crosses are not currently feasible. Here we report on the development of two additional markers: pac, conferring resistance to the glycopeptide antibiotic puromycin, and phleo, conferring resistance to the DNA-binding drug phleomycin. We constructed a set of four analogous shuttle vectors with these four markers, using DNA segments flanking the Leishmania major H region hmtxr gene to provide information required for expression. These constructs (pHM-NEO, pHM-HYG, pHM-PAC and pHM-PHLEO) were successfully transfected into L. major, mostly with efficiencies comparable to those observed with previous DHFR-TS-based neo and hyg-containing constructs. The exception was pHM-PHLEO, which transfected 30-fold less efficiently; this may be related to the nonenzymatic mechanism of resistance encoded by phleo. All four constructs were shown to replicate extra-chromosomally. Stable transfectants bearing all paired combinations of pHM constructs were obtained by a second round of transfection. These data show that the four markers are functionally independent and in conjunction with the Leishmania N-acetylglucosaminyl transferase gene, brings the number of selectable markers available in Leishmania to five.
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PMID:Two more independent selectable markers for stable transfection of Leishmania. 811 24