Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent studies have indicated a normal gene dose for the amyloid precursor protein (APP) in Alzheimer's disease (AD). These findings leave open the possibility that elevated levels of messenger RNA (mRNA) for this protein may contribute to the pathogenesis of AD. Using Northern analysis, we compared the levels of mRNA for the APP and 3 cytoskeletal proteins in parietal cortex of 6 brains having marked AD-type degeneration with the levels of these mRNAs in 6 control samples. The cytoskeletal mRNAs studied were those for the human neurofilament 68-kDa subunit (HNFL), for alpha-tubulin, and for glial fibrillary acidic protein (GFAP). A ribonuclease (RNase) protection assay was also used to compare AD and control HNFL mRNA levels. The mRNAs for APP, HNFL, and alpha-tubulin were diminished in AD cortex. The decrement for APP mRNA was less than that for HNFL or alpha-tubulin. The message for GFAP in AD cortex showed no loss. The findings support a general deficit in neuronal mRNAs, including that for APP. They do not exclude the possibility of elevated levels of the message for the APP in small neuronal subsets, in subcortical neurons projecting to cortex, or as a generalized phenomenon in earlier stages of the disease.
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PMID:Altered expression of genes for amyloid and cytoskeletal proteins in Alzheimer cortex. 246 80

A Chinese hamster alpha-tubulin cDNA was modified to encode an 11-amino acid carboxyl-terminal extension containing the immunodominant epitope from influenza hemagglutinin antigen (to create HA alpha 1-tubulin) and was cloned into a vector for expression in mammalian cells. 12 stable CHO cell lines expressing this HA alpha 1-tubulin were isolated and characterized. HA alpha 1-tubulin incorporated into all classes of microtubules, assembled to the same extent as the endogenous tubulin, and did not perturb the growth of the cells in which it was expressed. However, overexpression of HA alpha 1-tubulin strongly repressed the synthesis of endogenous alpha-tubulin while having little or no effect on the synthesis of beta-tubulin. Treatment of transfected cells with sodium butyrate to induce even greater expression of HA alpha 1-tubulin led to a further decrease in synthesis of endogenous alpha-tubulin that was fully reversible upon removal of the inducer. Decreased synthesis of alpha-tubulin in transfected cells did not result from decreased levels of alpha-tubulin mRNA, as demonstrated by ribonuclease protection assays. On the other hand, colchicine, a drug previously shown to destabilize the tubulin message, caused a clear reduction in both protein synthesis and mRNA levels for transfected HA alpha 1-tubulin and endogenous alpha-tubulin, thus indicating that the decreased alpha-tubulin synthesis observed as a result of HA alpha 1-tubulin overexpression is distinct from the previously described autoregulation of tubulin. The results are consistent with a mechanism in which free alpha-tubulin inhibits the translation of its own message as a way of ensuring stoichiometric synthesis of alpha- and beta-tubulin.
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PMID:alpha-Tubulin limits its own synthesis: evidence for a mechanism involving translational repression. 897 20

Cotton (Gossypium hirsutum L.) fibers are single-celled trichomes that synchronously undergo a phase of rapid cell expansion, then a phase including secondary cell wall deposition, and finally maturation. To determine if there is coordinated regulation of gene expression during fiber expansion, we analyzed the expression of components involved in turgor regulation and a cytoskeletal protein by measuring levels of mRNA and protein accumulation and enzyme activity. Fragments of the genes for the plasma membrane proton-translocating ATPase, vacuole-ATPase, proton-translocating pyrophosphatase (PPase), phosphoenolpyruvate carboxylase, major intrinsic protein, and alpha-tubulin were amplified by polymerase chain reaction and used as probes in ribonuclease protection assays of RNA from a fiber developmental series, revealing two discrete patterns of mRNA accumulation. Transcripts of all but the PPase accumulated to highest levels during the period of peak expansion (+12-15 d postanthesis [dpa]), then declined with the onset of secondary cell wall synthesis. The PPase was constitutively expressed through fiber development. Activity of the two proton-translocating-ATPases peaked at +15 dpa, whereas PPase activity peaked at +20 dpa, suggesting that all are involved in the process of cell expansion but with varying roles. Patterns of protein accumulation and enzyme activity for some of the proteins examined suggest posttranslational regulation through fiber development.
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PMID:Genes involved in osmoregulation during turgor-driven cell expansion of developing cotton fibers are differentially regulated. 953 73