RESUMO
The primary sequence of a cDNA encoding a novel transglutaminase from a human prostate cDNA library is reported. The sequence is compared to other known transglutaminases in a multiple alignment. The deduced peptide sequence is 51% identical to a rat prostate transglutaminase.
Assuntos
Clonagem Molecular , DNA Complementar/química , Próstata/química , Transglutaminases/genética , Sequência de Aminoácidos , Composição de Bases , Sequência de Bases , Códon , DNA Complementar/genética , Humanos , Masculino , Dados de Sequência Molecular , Alinhamento de Sequência , Transglutaminases/químicaRESUMO
Glutamine:fructose-6-phosphate amidotransferase (GFAT) has recently been shown to be an insulin-regulated enzyme that plays a key role in the induction of insulin resistance in cultured cells. As a first step in understanding the molecular regulation of this enzyme the human form of this enzyme has been cloned and the functional protein has been expressed in Escherichia coli. A 3.1-kilobase cDNA was isolated which contains the complete coding region of 681 amino acids. Expression of the cDNA in E. coli produced a protein of approximately 77 kDa and increased GFAT activity 4.5-fold over endogenous bacterial levels. Recombinant GFAT activity was inhibited 51% by UDP-GlcNAc whereas bacterial GFAT activity was insensitive to inhibition by UDP-GlcNAc. On the basis of these results we conclude that: 1) functional human GFAT protein was expressed, and 2) the cloned human cDNA encodes both the catalytic and regulatory domains of GFAT since the recombinant GFAT was sensitive to UDP-GlcNAc. Overall, the development of cloned GFAT molecular probes should provide new insights into the development of insulin resistance by allowing quantitation of GFAT mRNA levels in pathophysiological states such as non-insulin-dependent diabetes mellitus and obesity.
Assuntos
DNA/genética , Escherichia coli/genética , Glutamina-Frutose-6-Fosfato Transaminase (Isomerizante)/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Glutamina-Frutose-6-Fosfato Transaminase (Isomerizante)/isolamento & purificação , Glutamina-Frutose-6-Fosfato Transaminase (Isomerizante)/metabolismo , Humanos , Cinética , Dados de Sequência Molecular , Peso Molecular , Oligodesoxirribonucleotídeos , Reação em Cadeia da Polimerase , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Homologia de Sequência de AminoácidosRESUMO
Alveolar macrophages (AM) mediate lung inflammation by producing lipid and peptide molecules that attract neutrophils (PMN) to the lung. Recently we described two porcine proteins called alveolar macrophage-derived chemotactic factors, AMCF-I and -II, that are potent, efficacious, and specific PMN chemoattractants both in vitro and in vivo. We report here the cloning of the full-length cDNAs which code for each protein. Porcine AM were stimulated for 4 h in vitro with Escherichia coli endotoxin (LPS), and a cDNA library was created from poly(A)(+)-selected mRNA. Specific oligonucleotide probes for AMCF-I and AMCF-II were amplified from the porcine AM cDNA library by the polymerase chain reaction using degenerate oligonucleotide primer pairs derived from the N-terminal amino acid sequences of the proteins. These probes were used to isolate 2 full-length cDNAs of 1466 (AMCF-I) and 1515 (AMCF-II) base pairs. Both cDNAs code for proteins with four cysteine residues containing the C-X-C sequence characteristic of the intercrine-alpha family of neutrophil chemoattractants. AMCF-I shares 74% identity with human IL-8 and 84% identity with rabbit IL-8, and likely represents the porcine homologue of IL-8. By contrast, AMCF-II has no obvious human homologue. AMCF-II shares 53% identity with human neutrophil activating peptide 2. Its shared identity with the GRO-related proteins is as high as 61% (rat CINC/GRO), and its shared identity with the 78 amino acid epithelial cell-derived neutrophil activator (ENA-78) is 67%. AMCF-II may represent a new member of the intercrine-alpha family of neutrophil chemoattractants.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Fatores Quimiotáticos/química , Fatores Quimiotáticos/genética , Interleucina-8/química , Macrófagos Alveolares/química , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Clonagem Molecular , DNA , Dados de Sequência Molecular , Neutrófilos , Reação em Cadeia da Polimerase , RNA Mensageiro/metabolismo , Homologia de Sequência de Aminoácidos , SuínosRESUMO
Human progalanin cDNA was cloned with polymerase chain reaction techniques. The cDNA sequence predicts that the human form of galanin has a substitution of the glycine residue found at position 30 in other species and thus is likely to retain this residue during posttranslational processing and not be amidated at the COOH terminus. Furthermore, the cDNA sequence predicts three additional amino acid substitutions compared with known galanins. Human galanin was synthesized, and its bioactivity was compared with porcine and rat galanin based on inhibition of insulin release from a glucose-responsive rat insulinoma (RIN) cell line. Human galanin inhibited glucose-stimulated insulin secretion in a dose-dependent manner in RIN cells. Human, porcine, and rat galanin exhibited similar activity with ED50 less than 1 nM.
