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Query: UNIPROT:P11021 (BiP)
 2,049 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plastids of diatoms and related algae are delineated by four membranes: the outermost membrane (CER) is continuous with the endoplasmic reticulum while the inner two membranes are homologous to plastid envelope membranes of vascular plants and green algae. Proteins are transported into these plastids by pre-sequences that have two recognizable domains. To characterize targeting of polypeptides within diatom cells, we generated constructs encoding green fluorecent protein (GFP) fused to leader sequences. A fusion of GFP to the pre-sequence of BiP [an endoplasmic reticulum (ER)-localized chaperone] resulted in accumulation of GFP within the ER; a construct encoding the pre-sequence of a plastid protein fused to GFP was directed into the plastids. Additional constructs demonstrated that the N-terminal region of the bipartite plastid targeting pre-sequence was necessary for transport of polypeptides to the lumen of the ER, while the C-terminal region was shown to enable the proteins to traverse the plastid double envelope membrane. Our data strongly support the hypothesis of a multi-step plastid targeting process in chromophytic algae and raises questions about the continuity of the ER and CER and the function of the latter in polypeptide trafficking.
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PMID:In vivo characterization of diatom multipartite plastid targeting signals. 1235 11

The objectives of this study are to examine hepatic gene expression changes caused by GH transgenesis and enhanced growth. This is the first use of cDNA microarrays to study the influence of GH transgenesis on liver gene expression in a non-mammalian vertebrate, and the first such study using sexually immature animals. Three groups of coho salmon were examined: GH transgenic on full ration (T), GH transgenic on restricted ration (R), and control non-transgenic (C). Specific growth rates for weight in T were approximately eightfold higher than in C, and fourfold higher than in R. Differential gene expression in T, R, and C samples was determined using approximately 3500 and 16,000 gene microarrays, and R and C samples were compared on a different approximately 4000 gene microarray. The use of multiple microarray platforms increased the overall proportion of the hepatic transcriptome considered in these studies. Cross-platform comparisons identified genes behaving similarly between studies. For example, genes encoding a precerebellin-like protein and complement component C3 were downregulated in R relative to C (R < C) in two microarray studies, and hemoglobins alpha and beta were R > C in all three studies. Comparisons of informative gene lists within and between studies inferred causes of altered gene expression. For example, ten genes, including 78 kDa glucose-regulated protein, glycerol-3-phosphate dehydrogenase, hemoglobins alpha and beta, and a C-type lectin, were likely induced by GH transgenesis due to their presence in both T > C and R > C gene lists. Eleven genes, including hepcidin, nuclear protein p8, precerebellin-like, transketolase, and fatty acid-binding protein, were present in both T < C and R < C gene lists and were, therefore, likely suppressed by GH transgenesis. A large number of salmonid genes identified in these studies are involved in iron homeostasis, mitochondrial function, carbohydrate metabolism, cellular proliferation, and innate immunity. Pentose phosphate pathway genes phosphogluconate dehydrogenase, transaldolase, and transketolase, were dysregulated in GH transgenic samples relative to control samples. Changes in the expression of genes involved in maintaining hemoglobin levels (heme oxygenase, hemoglobins alpha and beta, Kruppel-like globin gene activator, hepcidin) in R and T fish indicate a need for additional hemoglobin in the transgenic fish, perhaps due to higher metabolic rate required for enhanced growth.
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PMID:Multiple microarray platforms utilized for hepatic gene expression profiling of GH transgenic coho salmon with and without ration restriction. 1703 44