Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The structural organization of the entire nuclear gene (NMDMC) encoding the mitochondrial (mt) NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase enzyme (NMDMC) was determined by analysis of clones obtained from a lambda EMBL3 murine genomic DNA library. The gene is approx. 13 kb in length and contains eight exons and seven introns. All exon/intron splice junctions follow the GT/AG rule. The amino acid presequence, which is essential for transport of the NMDMC enzyme precursor into mt, is encoded almost entirely in the first exon. Two major transcriptional start points (tsp), located 33 and 75 nucleotides upstream from the AUG start codon, were revealed by S1 nuclease mapping and RNase protection analyses. The immediate 5'-flanking region of the first exon contains one CAAT box, a TATA-like box and three sites homologous to the consensus sequence for the binding of transcription factor Sp1.
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PMID:Structural organization of the murine gene encoding NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase. 199 93

Cytosolic NADP-dependent methylenetetrahydrofolate dehydrogenase-cyclohydrolase synthetase and the mitochondrial NAD-dependent methylenetetrahydrofolate dehydrogenase-cyclohydrolase (NMDMC) are differentially expressed during insect development although both enzymes are detectable at all stages. In contrast, cell lines derived from a variety of insect species express high levels of NMDMC but undetectable levels of the NADP-dependent enzyme. Northern analysis indicates the NMDMC message is expressed at levels 50-100 times higher in a Drosophila cell line compared to adult flies. RNase protection showed the predominance of shortened transcripts that require initiation at a downstream AUG producing a truncated protein that lacks a mitochondrial targeting sequence. These changes in expression effectively exchange the cytosolic NADP-dependent dehydrogenase for one with NAD specificity.
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PMID:NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase is targeted to the cytoplasm in insect cell lines. 761 77