Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.3 (complex I)
 8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Though previously described as very low or absent in yeast, we find significant pyridine nucleotide transhydrogenation (NADPH + acetyl pyridine-NAD+----NADP+ + acetyl pyridine-NADH) activity in yeast extracts when assayed at pH 8-9, and describe here the subcellular distribution and separation of the various molecular forms contributing to the total activity in two yeast species. Gentle subcellular fractionation reveals transhydrogenase activity only in the cytosolic fraction of both Saccharomyces cerevisiae and Candida utilis while intact mitochondria and microsomes are without activity. On sucrose gradient centrifugation, this soluble cytosolic activity proves to be primarily in a high-molecular-weight (greater than 10(6)) band which has salmon-colored fluorescence on uv illumination. Sonication of the particulate subcellular fractions solubilizes substantial transhydrogenase activity from mitochondria of C. utilis (but not from S. cerevisiae) which on sucrose gradients consists of both high (greater than 10(6))- and low-molecular-weight active fractions, each with yellow-green fluorescence. Ammonium sulfate fractionation and sucrose gradient centrifugation of protein solubilized from whole yeast of both species by vigorous homogenization with glass beads confirms the presence and fluorescence of these various molecular weight forms. The relationship of these activities to other enzymatic activities (especially the mitochondrial external NADH dehydrogenase) is discussed.
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PMID:Pyridine nucleotide transhydrogenations in yeast. 390 68

Reprogramming of a gene's expression pattern by acquisition and loss of sequences recognized by specific regulatory RNA binding proteins may be a major mechanism in the evolution of biological regulatory programs. We identified that RNA targets of Puf3 orthologs have been conserved over 100-500 million years of evolution in five eukaryotic lineages. Focusing on Puf proteins and their targets across 80 fungi, we constructed a parsimonious model for their evolutionary history. This model entails extensive and coordinated changes in the Puf targets as well as changes in the number of Puf genes and alterations of RNA binding specificity including that: 1) Binding of Puf3 to more than 200 RNAs whose protein products are predominantly involved in the production and organization of mitochondrial complexes predates the origin of budding yeasts and filamentous fungi and was maintained for 500 million years, throughout the evolution of budding yeast. 2) In filamentous fungi, remarkably, more than 150 of the ancestral Puf3 targets were gained by Puf4, with one lineage maintaining both Puf3 and Puf4 as regulators and a sister lineage losing Puf3 as a regulator of these RNAs. The decrease in gene expression of these mRNAs upon deletion of Puf4 in filamentous fungi (N. crassa) in contrast to the increase upon Puf3 deletion in budding yeast (S. cerevisiae) suggests that the output of the RNA regulatory network is different with Puf4 in filamentous fungi than with Puf3 in budding yeast. 3) The coregulated Puf4 target set in filamentous fungi expanded to include mitochondrial genes involved in the tricarboxylic acid (TCA) cycle and other nuclear-encoded RNAs with mitochondrial function not bound by Puf3 in budding yeast, observations that provide additional evidence for substantial rewiring of post-transcriptional regulation. 4) Puf3 also expanded and diversified its targets in filamentous fungi, gaining interactions with the mRNAs encoding the mitochondrial electron transport chain (ETC) complex I as well as hundreds of other mRNAs with nonmitochondrial functions. The many concerted and conserved changes in the RNA targets of Puf proteins strongly support an extensive role of RNA binding proteins in coordinating gene expression, as originally proposed by Keene. Rewiring of Puf-coordinated mRNA targets and transcriptional control of the same genes occurred at different points in evolution, suggesting that there have been distinct adaptations via RNA binding proteins and transcription factors. The changes in Puf targets and in the Puf proteins indicate an integral involvement of RNA binding proteins and their RNA targets in the adaptation, reprogramming, and function of gene expression.
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PMID:Evolutionary Conservation and Diversification of Puf RNA Binding Proteins and Their mRNA Targets. 2658 79