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Amino Acid Polypeptide (amino + acid_polypeptide)
Selected AbstractsHypoxia induces expression of a GPI-anchorless splice variant of the prion proteinFEBS JOURNAL, Issue 11 2008Yutaka Kikuchi The human prion protein (PrP) is a glycoprotein with a glycosylphosphatidylinositol (GPI) anchor at its C-terminus. Here we report alternative splicing within exon 2 of the PrP gene (PRNP) in the human glioblastoma cell line T98G. The open reading frame of the alternatively spliced mRNA lacked the GPI anchor signal sequence and encoded a 230 amino acid polypeptide. Its product, GPI-anchorless PrP (GPI, PrPSV), was unglycosylated and soluble in non-ionic detergent, and was found in the cytosolic fraction. We also detected low levels of alternatively spliced mRNA in human brain and non-neuronal tissues. When long-term passaged T98G cells were placed in a low-oxygen environment, alternatively spliced mRNA expression increased and expression of normally spliced PrP mRNA decreased. These findings imply that oxygen tension regulates GPI, PrPSV expression in T98G cells. [source] A novel gene, ecl1+, extends the chronological lifespan in fission yeastFEMS YEAST RESEARCH, Issue 4 2008Hokuto Ohtsuka Abstract We have identified a novel gene from Schizosaccharomyces pombe that we have named ecl1+ (extender of the chronological lifespan). When ecl1+ is provided on a high-copy number plasmid, it extends the viability of both the ,sty1 MAP kinase mutant and the wild-type cells after entry into the stationary phase. ecl1+ encodes an 80-amino acid polypeptide that had not been annotated in the current database. The ecl1+ -mRNA increases transiently when the growth phase is changed from the log phase to the stationary phase. The Ecl1 protein is localized in the nucleus. Calorie restriction extends the chronological lifespan of wild-type and ,ecl1 cells but not ecl1+ -overproducing cells. The ,pka1 mutant shows little, if any, additional extension of viability when Ecl1 is overproduced. The ste11+ gene that is negatively controlled by Pka1 is up regulated when Ecl1 is overproduced. From these results we propose that the effect of Ecl1 overproduction may be mainly linked to and negatively affects the Pka1-dependent pathway. [source] Characterization of heat shock protein 90 in the shrimp Metapenaeus ensis: Evidence for its role in the regulation of vitellogenin synthesisMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 5 2008Long Tao Wu Abstract Estrogen hormones play a vital role in the regulation of female reproductive maturation. In oviparous vertebrates, the synthesis of vitellogenin (VTG) is tightly controlled by estrogen hormone signal transduction pathway, which is mediated by estrogen receptor and heat shock protein 90 (Hsp90). In order to investigate whether a similar mechanism exists in crustaceans, the Hsp90 gene was cloned and isolated from the shrimp Metapenaeus ensis by homology cloning strategy. The Hsp90 is 2,524 bp in length, containing an open reading frame of 2,163 bp that encodes a 720 amino acid polypeptide (83 kD). The Hsp90 -coding region is interrupted by four introns. MeHsp90 is differentially expressed in eyestalk, ovary, and hepatopancreas at different ovarian maturation stages, and consistently expressed in other tissues including heart, gill, gut, muscle, and central nervous system. In vitro ovary explant assay reveals that MeHsp90 expression in immature ovary can be induced by the addition of exogenous estradiol-17,, but expression in fully mature ovary exhibits no response to estradiol-17, treatment. In situ hybridization shows that MeHsp90 is highly expressed in previtellogenic oocytes and its expression decreases with the progress of maturation, and finally stops in late-vitellogenic oocytes. Our results indicate a strong correlation between estrogen hormones and Hsp90 expression in shrimp, suggesting that the expression of VTG may be under the regulation of estrogen hormones through a mechanism similar to that in vertebrates. The result provides insights on the control of vitellogenesis in invertebrates. Mol. Reprod. Dev. 75: 952,959, 2008. © 2008 Wiley-Liss, Inc. [source] Research note: Characterization of a cDNA encoding glutamine synthetase II from Gelidium crinale (Rhodophyta)PHYCOLOGICAL RESEARCH, Issue 1 2002D. Wilson Freshwater SUMMARY A cDNA encoding glutamine synthetase (GS) was characterized from the red alga, Gelidium crinale (Turner) Gaillon, using reverse-transcriptase polymerase chain reaction and the 5,- and 3,-rapid amplification of cDNA ends. Sequence analysis of a 1231-bp GS cDNA transcript included both 5, and 3, untranslated regions and a 1056-bp open reading frame encoding a 352 amino acid polypeptide. Comparison with GS sequences from other organisms revealed that the G. crinale cDNA encodes a type-II GS, and the absence of a N-terminal plastid signal sequence suggests that it is a cytosolic isoenzyme. Phylogenetic analyses of GSII amino acid sequences supports the multiple origin of cytosolic and plastid isoenzymes during eukaryotic evolution. [source] Characterization of a Cryptosporidium parvum Gene Encoding a Protein with Homology to Long Chain Fatty Acid SynthetaseTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2003Leonardo Camero ABSTRACT: We describe here the cloning, sequencing, and characterization of a novel Cryptosporidium parvum gene, encoding a protein with significant homology to the long-chain fatty acyl-CoA synthetase (LCFA, EC 6.2.13). The gene has an open reading frame of 2,301 bp, coding for a 766 amino acid polypeptide, and with an estimated MW of 86.1 kDa. By indirect immunofluorescence assay, monoclonal antibodies C3CE7 and ESD labeled the anterior pole of fixed C. parvum sporozoites and developmental stages in C. parvum-infected cultures at 24, 48, and 72 h post-infection. These monoclonal antibodies inhibited more than 3.5% of parasite growth in vitro. The effect of triacsin C, a potent selective inhibitor of LCFA synthetase, on parasite growth was assessed in cell culture; complete inhibition of parasite growth at 2.5 ug/inl was obtained with little evidence of drug-associated cytotoxicity. These results suggest that the fatty acyl-CoA synthetase may be a useful target in the development of selective inhibitors and immunologic interventions against C. parvum [source] Molecular cloning and characterization of ATX1 cDNA from the mole cricket, Gryllotalpa orientalisARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 4 2006Iksoo Kim Abstract To search for an insect homologue of antioxidant protein 1 (ATX1), a mole cricket, Gryllotalpa orientalis, cDNA library was screened and a cDNA clone, which encodes a 73 amino acid polypeptide with a predicted molecular mass of 8.0 kDa and pI of 5.68, was isolated. The G. orientalis ATX1 (GoATX1) cDNA features both a MTCXXC copper-binding site in the N-terminus and a KTGK lysine-rich region in the C-terminus. The deduced amino acid sequence of the GoATX1 cDNA showed 63% identity to Drosophila melanogaster ATX1 and 55% to Ixodes pacificus ATX1. Northern blot analysis revealed the presence of GoATX1 transcripts in midgut, fat body, and epidermis. When H2O2 was injected into the body cavity of G. orientalis adult, GoATX1 mRNA expression was up-regulated in the fat body tissue. Fat body expression level of GoATX1 mRNA in the fat body was increased following exposure to low (4°C) and high (37°C) temperatures, suggesting that GoATX1 plays a protective role against oxidative stress caused by temperature shock. This is the first report about a functional role of insect ATX1 in antioxidant defense. Arch. Insect Biochem. Physiol. 61:231,238, 2006. © 2006 Wiley-Liss, Inc. [source] | |||||||||||||