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)

The molecular karyotype of a murine isolate of Encephalitozoon cuniculi, a microsporidian with a wide range of mammalian hosts, comprises eleven chromosomes ranging in size between 217 and 315 kb. To determine specific chromosomal markers, a partial genomic library was constructed and cloned DNA fragments were hybridized to chromosomal bands separated by pulsed-field gel electrophoresis. Most probes were assigned to single chromosomes, indicating prevalence of low-copy number nucleotide sequences within the very small genome of E. cuniculi (2.9 Mb). A few probes were shown to hybridize to all chromosomes. These repetitive DNA fragments corresponded to either rRNA genes or some non-coding regions whose sequences were characterized by short micro- and minisatellites. The chromosomal locations of beta-tubulin genes and six newly identified protein-encoding genes were determined. Genes encoding dihydrofolate reductase, thymidylate synthase, serine hydroxymethyl transferase, a cdc2 kinase-like protein and helicase ERCC6-like protein were each located on a single chromosome whereas genes for both beta-tubulin and aminopeptidase were on two different chromosomes. The mapping will serve as a reference for further analysis of intraspecific karyotype polymorphism in different isolates from different host species.
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PMID:Mapping of repetitive and non-repetitive DNA probes to chromosomes of the microsporidian Encephalitozoon cuniculi. 921 May 86

Alternative polyadenylation leads to mRNAs with variable 3' ends. Since a 3'-untranslated region (3'-UTR) often contains cis elements that impact stability or localization of mRNA or translation, selection of poly(A) sites in a 3'-UTR is regulated in mammalian cells. However, the molecular basis for alternative poly(A) site selection within a 3'-UTR has been unclear. Here we show involvement of cleavage factor Im (CFIm) in poly(A) site selection within a 3'-UTR. CFIm is a heterodimeric 3' end-processing complex, which functions to assemble other processing factors on pre-mRNA in vitro. We knocked down 25 kDa subunit of CFIm (CFIm25) in HeLa cells and analyzed alternative poly(A) site selection of TIMP-2, syndecan2, ERCC6 and DHFR genes by northern blotting. We observed changes in the distribution of mRNAs in CFIm25 depleted cells, suggesting a role for CFIm in alternative poly(A) site selection. Furthermore, tissue specific analysis demonstrated that the CFIm25 gene gave rise to 1.1, 2.0 and 4.6 kb mRNAs. The 4.6 kb mRNA was ubiquitously expressed, while the 1.1 and 2.0 kb mRNAs were expressed in a tissue specific manner. We found three likely poly(A) sites in the CFIm25 3'-UTR, suggesting alternative polyadenylation. Our results indicate that alternative poly(A) site selection is a well-regulated process in vivo.
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PMID:Knock-down of 25 kDa subunit of cleavage factor Im in Hela cells alters alternative polyadenylation within 3'-UTRs. 1709 38