The complement cofactor protein (SBP1) from the barred sand bass (Paralabrax nebulifer) mediates overlapping regulatory activities of both human C4b binding protein and factor H

We have previously shown that serum of the teleost fish barred sand bass (Paralabrax nebulifer) cleaves the alpha'-chain of human C4b and C3b. The proteins that participate in these reactions were purified, and a specific protease and a single cofactor protein were identified. Functional characterization of the recombinantly expressed sand bass cofactor protein (SBP1) and truncated forms containing short consensus repeats (SCRs) 1-2, 1-3, 1-4, 1-5, and 12-17 revealed that SBP1 and SCRs 1-4 mediate the functional activities of the human plasma regulatory protein C4bp and factor H. They form a complex with C4b, inhibit the formation, and accelerate the decay of the classical pathway C3 convertase and display cofactor activity for the cleavage of C4b. In contrast, the interaction of SBP1 and SCRs 1-4 with human C3b in all these activities was limited. This difference is due to species-specific incompatibilities between the cofactor protein and human C3b. SBP1 and SCRs 1-5 displayed full binding and cofactor activity for methylamine-treated C3 from trout, a species closely related to the sand bass. The presence of only one cofactor in the fish plasma that combines the functional activities of C4bp and factor H demonstrates that the sand bass cofactor protein is the ancestral precursor to the two complement regulatory proteins in human plasma.     

cDNA sequence and chromosomal localization of the remaining three human nuclear encoded iron sulphur protein (IP) subunits of complex I: the human IP fraction is completed

NADH:ubiquinone oxidoreductase (complex I) of the mitochondrial respiratory chain can be fragmented in a flavoprotein (FP), iron-sulfur protein (IP), and hydrophobic protein (HP) subfraction. The IP subfraction is hypothesized to be significant, since it contains important prosthetic groups highly conserved among species. We cloned the cDNA of three remaining human NADH:ubiquinone oxidoreductase subunits of this IP fraction: the NDUFS2 (49 kDa), NDUFS3 (30 kDa), and NDUFS6 (13 kDa) subunits. All presented cDNAs include the complete open reading frame (ORF), which consist of 1392, 795, and 375 base pairs, coding for 463, 264, and 124 amino acids, respectively. The latter show 96, 90, and 83% homology with the corresponding bovine translation products. The 3' untranslated regions (UTR) are complete in all three cDNAs. Polymerase chain reaction performed with DNA isolated from somatic human-rodent cell hybrids containing defined human chromosomes as template gave a human-specific signal which mapped the NDUFS2 and NDUFS3 subunits to chromosomes 1 and 11, respectively. In the case of the NDUFS6 subunit a pseudogene may be present since signals were seen in the lanes containing chromosomes 5 and 6. The NDUFS2 contains a highly conserved protein kinase C phosphorylation site and the NDUFS3 subunit contains a highly conserved casein kinase II phosphorylation site which make them strong candidates for future mutation detection studies in enzymatic complex I-deficient patients.     

Tonoplast intrinsic proteins from cauliflower (Brassica oleracea L. var. botrytis): immunological analysis, cDNA cloning and evidence for expression in meristematic tissues

Chemokine production by human retinal pigment epithelium (HRPE) cells is believed to play an important role in ocular inflammation and immune responses. In our previous studies, we demonstrated that glycated human serum albumin (GHSA) strongly stimulates HRPE cells and human corneal keratocytes to produce chemokines. In the present study, we further examined the effects of GHSA on TNF-alpha- and IL-1 beta-induced HRPE IL-8 and monocyte chemoattractant protein (MCP)-1 gene expression and protein secretion in HRPE. At maximally effective concentrations, GHSA (2000 micrograms/ml) potentiated TNF-alpha (20 ng/ml)-stimulated HRPE IL-8 secretion approximately 7-fold. Consistent with the above observations were the time- and dose-dependent increases in the steady-state IL-8 mRNA after coadministration with these two factors, although the half-life of IL-8 mRNA (30 minutes) was not altered by GHSA. In contrast to IL-8, the TNF-alpha-induced HRPE MCP-1 gene expression was only slightly enhanced by GHSA. Moreover, potentiation of HRPE IL-8 generation by GHSA appeared to be selective for TNF-alpha because, under similar conditions, GHSA was unable to enhance the IL-1 beta-stimulated IL-8 gene expression and protein secretion. The IL-1 beta-stimulated HRPE MCP-1 production was also unchanged by GHSA. Collectively, these results suggest specific potentiation of TNF-alpha-induced HRPE IL-8 by human serum albumin that has been glycated either during circulation or locally within tissue. This interaction may be relevant to a variety of ocular diseases involving breakdown of the blood-retinal barrier.     

Cloning and chromosome assignment to 1q32 of a human cDNA (RAB7L1) encoding a small GTP-binding protein, a member of the RAS superfamily

A full-length cDNA homologous to RAB7, a member of the RAB-related GTP-binding protein subfamily, was isolated from a human placenta cDNA library. This cDNA, designated RAB7L1, has an open reading frame of 609 nucleotides encoding 203 amino acids. Northern analysis showed that the mRNA is ubiquitously expressed in human tissues, although signal intensities were different among the various organs examined. This gene was located on chromosome band 1q32 by fluorescence in situ hybridization.     

Changes of plasma levels of human growth hormone with age in relation to mammary tumour appearance in whey acidic protein/human growth hormone (mWAP/hGH) transgenic female and male mice

Plasma levels of human growth hormone (hGH) were determined in female and male transgenic mice with human growth hormone fusion gene driven by the promoter of mouse whey acidic protein (mWAP/hGH) at 3, 6 and 9 months of age and at mammary tumour appearance. In female transgenic mice developing mammary tumours, the plasma hGH level decreased markedly upon tumour appearance, which was associated with little change in body weight. In contrast, the hGH level changed little in transgenic male mice with tumours. In female and male transgenic mice without mammary tumours, the pattern of the change of hGH levels was variable; some showed high levels at all three time points (3, 6, and 9 months) and others had none or high levels at one or two time points.