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At least 991 records · Page 55Linked to original sources
PubMed2005

Syncytin-A and syncytin-B, two fusogenic placenta-specific murine envelope genes of retroviral origin conserved in Muridae.

Recently, we and others have identified two human endogenous retroviruses that entered the primate lineage 25-40 million years ago and that encode highly fusogenic retroviral envelope proteins (syncytin-1 and -2), possibly involved in the formation of the placenta syncytiotrophoblast layer generated by trophoblast cell fusion at the materno-fetal interface. A systematic in silico search throughout mouse genome databases presently identifies two fully coding envelope genes, present as unique copies and unrelated to any known murine endogenous retrovirus, that we named syncytin-A and -B. Quantitative RT-PCR demonstrates placenta-specific expression for both genes, with increasing transcript levels in this organ from 9.5 to 14.5 days postcoitum. In situ hybridization of placenta cryosections further localizes these transcripts in the syncytiotrophoblast-containing labyrinthine zona. Consistently, we show that both genes can trigger cell-cell fusion in ex vivo transfection assays, with distinct cell type specificities suggesting different receptor usage. Genes orthologous to syncytin-A and -B and disclosing a striking conservation of their coding status are found in all Muridae tested (mouse, rat, gerbil, vole, and hamster), dating their entry into the rodent lineage approximately 20 million years ago. Together, these data strongly argue for a critical role of syncytin-A and -B in murine syncytiotrophoblast formation, thus unraveling a rather unique situation where two pairs of endogenous retroviruses, independently acquired by the primate and rodent lineages, would have been positively selected for a convergent physiological role.

Animals↗
PubMed2005

Fast and reliable prediction of noncoding RNAs.

We report an efficient method for detecting functional RNAs. The approach, which combines comparative sequence analysis and structure prediction, already has yielded excellent results for a small number of aligned sequences and is suitable for large-scale genomic screens. It consists of two basic components: (i) a measure for RNA secondary structure conservation based on computing a consensus secondary structure, and (ii) a measure for thermodynamic stability, which, in the spirit of a z score, is normalized with respect to both sequence length and base composition but can be calculated without sampling from shuffled sequences. Functional RNA secondary structures can be identified in multiple sequence alignments with high sensitivity and high specificity. We demonstrate that this approach is not only much more accurate than previous methods but also significantly faster. The method is implemented in the program rnaz, which can be downloaded from www.tbi.univie.ac.at/~wash/RNAz. We screened all alignments of length n > or = 50 in the Comparative Regulatory Genomics database, which compiles conserved noncoding elements in upstream regions of orthologous genes from human, mouse, rat, Fugu, and zebrafish. We recovered all of the known noncoding RNAs and cis-acting elements with high significance and found compelling evidence for many other conserved RNA secondary structures not described so far to our knowledge.

Algorithms↗
PubMed2005

Molecular cloning of TRPC3a, an N-terminally extended, store-operated variant of the human C3 transient receptor potential channel.

AK032317 is the GenBank accession no. of a full-length RIKEN mouse cDNA. It encodes a putative variant of the C3-type TRPC (transient receptor potential channel) that differs from the previously cloned murine TRPC3 cDNA in that it has a 5' extension stemming from inclusion of an additional exon (exon 0). The extended cDNA adds 62 aa to the sequence of the murine TRPC3. Here, we report the cloning of a cDNA encoding the human homologue of this extended TRPC3 having a highly homologous 73-aa N-terminal extension, referred to as hTRPC3a. A query of the GenBank genomic database predicts the existence of a similar gene product also in rats. Transient expression of the longer TRPC3a in human embryonic kidney (HEK) cells showed that it mediates Ca2+ entry in response to stimulation of the Gq-phospholipase C beta pathway, which is similar to that mediated by the shorter hTRPC3. However, after isolation of HEK cells expressing hTRPC3 in stable form, TRPC3a gave rise to Ca2+-entry channels that are not only activated by the Gq-phospholipase C beta pathway (receptor-activated Ca entry) but also by thapsigargin triggered store depletion. In conjunction with findings from our and other laboratories that TRPC1, TRPC2, TRPC4, TRPC5, and TRPC7, can each mediate store-depletion-activated Ca2+ entry in mammalian cells, our findings with hTRC3a support our previous proposal that TRPCs form capacitative Ca-entry channels.

Amino Acid Sequence↗
PubMed2001

Urocortin II: a member of the corticotropin-releasing factor (CRF) neuropeptide family that is selectively bound by type 2 CRF receptors.

Here we describe the cloning and initial characterization of a previously unidentified CRF-related neuropeptide, urocortin II (Ucn II). Searches of the public human genome database identified a region with significant sequence homology to the CRF neuropeptide family. By using homologous primers deduced from the human sequence, a mouse cDNA was isolated from whole brain poly(A)(+) RNA that encodes a predicted 38-aa peptide, structurally related to the other known mammalian family members, CRF and Ucn. Ucn II binds selectively to the type 2 CRF receptor (CRF-R2), with no appreciable activity on CRF-R1. Transcripts encoding Ucn II are expressed in discrete regions of the rodent central nervous system, including stress-related cell groups in the hypothalamus (paraventricular and arcuate nuclei) and brainstem (locus coeruleus). Central administration of 1-10 microg of peptide elicits activational responses (Fos induction) preferentially within a core circuitry subserving autonomic and neuroendocrine regulation, but whose overall pattern does not broadly mimic the CRF-R2 distribution. Behaviorally, central Ucn II attenuates nighttime feeding, with a time course distinct from that seen in response to CRF. In contrast to CRF, however, central Ucn II failed to increase gross motor activity. These findings identify Ucn II as a new member of the CRF family of neuropeptides, which is expressed centrally and binds selectively to CRF-R2. Initial functional studies are consistent with Ucn II involvement in central autonomic and appetitive control, but not in generalized behavioral activation.

Amino Acid Sequence↗
PubMed2002

Identification and characterization of a human DNA glycosylase for repair of modified bases in oxidatively damaged DNA.

8-oxoguanine (8-oxoG), ring-opened purines (formamidopyrimidines or Fapys), and other oxidized DNA base lesions generated by reactive oxygen species are often mutagenic and toxic, and have been implicated in the etiology of many diseases, including cancer, and in aging. Repair of these lesions in all organisms occurs primarily via the DNA base excision repair pathway, initiated with their excision by DNA glycosylase/AP lyases, which are of two classes. One class utilizes an internal Lys residue as the active site nucleophile, and includes Escherichia coli Nth and both known mammalian DNA glycosylase/AP lyases, namely, OGG1 and NTH1. E. coli MutM and its paralog Nei, which comprise the second class, use N-terminal Pro as the active site. Here, we report the presence of two human orthologs of E. coli mutM nei genes in the human genome database, and characterize one of their products. Based on the substrate preference, we have named it NEH1 (Nei homolog). The 44-kDa, wild-type recombinant NEH1, purified to homogeneity from E. coli, excises Fapys from damaged DNA, and oxidized pyrimidines and 8-oxoG from oligodeoxynucleotides. Inactivation of the enzyme because of either deletion of N-terminal Pro or Histag fusion at the N terminus supports the role of N-terminal Pro as its active site. The tissue-specific levels of NEH1 and OGG1 mRNAs are distinct, and S phase-specific increase in NEH1 at both RNA and protein levels suggests that NEH1 is involved in replication-associated repair of oxidized bases.

Amino Acid Sequence↗
PubMed2003

A Bayesian framework for combining heterogeneous data sources for gene function prediction (in Saccharomyces cerevisiae).

Genomic sequencing is no longer a novelty, but gene function annotation remains a key challenge in modern biology. A variety of functional genomics experimental techniques are available, from classic methods such as affinity precipitation to advanced high-throughput techniques such as gene expression microarrays. In the future, more disparate methods will be developed, further increasing the need for integrated computational analysis of data generated by these studies. We address this problem with MAGIC (Multisource Association of Genes by Integration of Clusters), a general framework that uses formal Bayesian reasoning to integrate heterogeneous types of high-throughput biological data (such as large-scale two-hybrid screens and multiple microarray analyses) for accurate gene function prediction. The system formally incorporates expert knowledge about relative accuracies of data sources to combine them within a normative framework. MAGIC provides a belief level with its output that allows the user to vary the stringency of predictions. We applied MAGIC to Saccharomyces cerevisiae genetic and physical interactions, microarray, and transcription factor binding sites data and assessed the biological relevance of gene groupings using Gene Ontology annotations produced by the Saccharomyces Genome Database. We found that by creating functional groupings based on heterogeneous data types, MAGIC improved accuracy of the groupings compared with microarray analysis alone. We describe several of the biological gene groupings identified.

Algorithms↗
PubMed2002

Identification of oncogenes collaborating with p27Kip1 loss by insertional mutagenesis and high-throughput insertion site analysis.

The p27(Kip1) protein is a cyclin-dependent kinase inhibitor that blocks cell division in response to antimitogenic cues. p27 expression is reduced in many human cancers, and p27 functions as a tumor suppressor that exhibits haploinsufficiency in mice. Despite the well characterized role of p27 as a cyclin-dependent kinase inhibitor, its mechanism of tumor suppression is unknown. We used Moloney murine leukemia virus to induce lymphomas in p27+/+ and p27-/- mice and observed that lymphomagenesis was accelerated in the p27-/- animals. To identify candidate oncogenes that collaborate with p27 loss, we used a high-throughput strategy to sequence 277 viral insertion sites derived from two distinct sets of p27-/- lymphomas and determined their chromosomal location by comparison with the Celera and public (Ensembl) mouse genome databases. This analysis identified a remarkable number of putative protooncogenes in these lymphomas, which included loci that were novel as well as those that were overrepresented in p27-/- tumors. We found that Myc activations occurred more frequently in p27-/- lymphomas than in p27+/+ tumors. We also characterized insertions within two novel loci: (i) the Jun dimerization protein 2 gene (Jundp2), and (ii) an X-linked locus termed Xpcl1. Each of the loci that we found to be frequently involved in p27-/- lymphomas represents a candidate oncogene collaborating with p27 loss. This study illustrates the power of high-throughput insertion site analysis in cancer gene discovery.

Animals↗
PubMed2001

Incomplete taxon sampling is not a problem for phylogenetic inference.

A major issue in all data collection for molecular phylogenetics is taxon sampling, which refers to the use of data from only a small representative set of species for inferring higher-level evolutionary history. Insufficient taxon sampling is often cited as a significant source of error in phylogenetic studies, and consequently, acquisition of large data sets is advocated. To test this assertion, we have conducted computer simulation studies by using natural collections of evolutionary parameters--rates of evolution, species sampling, and gene lengths--determined from data available in genomic databases. A comparison of the true tree with trees constructed by using taxa subsamples and trees constructed by using all taxa shows that the amount of phylogenetic error per internal branch is similar; a result that holds true for the neighbor-joining, minimum evolution, maximum parsimony, and maximum likelihood methods. Furthermore, our results show that even though trees inferred by using progressively larger taxa subsamples of a real data set become increasingly similar to trees inferred by using the full sample, all inferred trees are equidistant from the true tree in terms of phylogenetic error per internal branch. Our results suggest that longer sequences, rather than extensive sampling, will better improve the accuracy of phylogenetic inference.

Amino Acids↗
PubMed2000

Lineage-specific loss and divergence of functionally linked genes in eukaryotes.

By comparing 4,344 protein sequences from fission yeast Schizosaccharomyces pombe with all available eukaryotic sequences, we identified those genes that are conserved in S. pombe and nonfungal eukaryotes but are missing or highly diverged in the baker's yeast Saccharomyces cerevisiae. Since the radiation from the common ancestor with S. pombe, S. cerevisiae appears to have lost about 300 genes, and about 300 more genes have diverged by far beyond expectation. The most notable feature of the set of genes lost in S. cerevisiae is the coelimination of functionally connected groups of proteins, such as the signalosome and the spliceosome components. We predict similar coelimination of the components of the posttranscriptional gene-silencing system that includes the recently identified RNA-dependent RNA polymerase. Because one of the functions of posttranscriptional silencing appears to be "taming" of retrotransposons, the loss of this system in yeast could have triggered massive retrotransposition, resulting in elimination of introns and subsequent loss of spliceosome components that become dispensable. As the genome database grows, systematic analysis of coordinated gene loss may become a general approach for predicting new components of functional systems or even defining previously unknown functional complexes.

Biological Evolution↗
PubMed1998

The area code hypothesis revisited: olfactory receptors and other related transmembrane receptors may function as the last digits in a cell surface code for assembling embryos.

Recent evidence emerging from several laboratories, integrated with new data obtained by searching the genome databases, suggests that the area code hypothesis provides a good heuristic model for explaining the remarkable specificity of cell migration and tissue assembly that occurs throughout embryogenesis. The area code hypothesis proposes that cells assemble organisms, including their brains and nervous systems, with the aid of a molecular-addressing code that functions much like the country, area, regional, and local portions of the telephone dialing system. The complexity of the information required to code cells for the construction of entire organisms is so enormous that we assume that the code must make combinatorial use of members of large multigene families. Such a system would reuse the same receptors as molecular digits in various regions of the embryo, thus greatly reducing the total number of genes required. We present the hypothesis that members of the very large families of olfactory receptors and vomeronasal receptors fulfill the criteria proposed for area code molecules and could serve as the last digits in such a code. We discuss our evidence indicating that receptors of these families are expressed in many parts of developing embryos and suggest that they play a key functional role in cell recognition and targeting not only in the olfactory system but also throughout the brain and numerous other organs as they are assembled.

Animals↗
PubMed1999

Genetic dissection of the budding yeast Arp2/3 complex: a comparison of the in vivo and structural roles of individual subunits.

In previous work, we identified the yeast Arp2/3 complex, which localizes to cortical actin patches and is required for their motility and integrity in vivo. This complex contains proteins homologous to each subunit of the Acanthamoeba and human Arp2/3 complex except for a 40-kDa subunit (p40), which was missing from the purified yeast complex. Here, we demonstrate by using immunoprecipitation and gel-filtration analysis that Arc40p, the homolog of p40 identified from the yeast genome database, associates with the yeast Arp2/3 complex. We have carried out gene disruptions of each subunit of the yeast Arp2/3 complex to study each subunit's role in the function of the complex. Surprisingly, we find that only ARC40 is fully essential for cell viability. Strains lacking each of the other subunits exhibit varying degrees of defects in cell growth and viability and in assembly and polarization of cortical actin patches. We have also examined each subunit's role in maintaining the structural integrity of the Arp2/3 complex. Arp2p, Arp3p, and Arc40p fall into the monomer pool in Deltaarc19 and Deltaarc35 cells, suggesting that Arc19p and Arc35p are the central scaffolding components of the complex. Arp2p and Arp3p do not have major roles in maintaining complex integrity, and Arc15p is required for association of Arp2p and Arc40p, but not other subunits, with the complex. These results provide evidence that each subunit contributes differently to the assembly and function of the Arp2/3 complex.

Acanthamoeba↗
PubMed1999

Drosophila proteins related to vertebrate DNA (5-cytosine) methyltransferases.

DNA methylation at CpG residues is closely associated with a number of biological processes during vertebrate development. Unlike the vertebrates, however, several invertebrate species, including the Drosophila, do not have apparent DNA methylation in their genomes. Nor have there been reports on a DNA (5-cytosine) methyltransferase (CpG MTase) found in these invertebrates. We now present evidence for two CpG MTase-like proteins expressed in Drosophila cells. One of these, DmMTR1, is a protein containing peptide epitopes immunologically related to the conserved motifs I and IV in the catalytic domain of the mammalian dnmt1. DmMTR1 has an apparent molecular mass of 220 kDa and, similar to mammalian dnmt1, it also interacts in vivo with the proliferating cell nuclear antigen. During interphase of the syncytial Drosophila embryos, the DmMTR1 molecules are located outside the nuclei, as is dnmt1 in the mouse blastocyst. However, DmMTR1 appears to be rapidly transported into, and then out of the nuclei again, as the embryos undergo mitotic waves. Immunofluorescent data indicate that DmMTR1 molecules "paint" the whole set of condensed Drosophila chromosomes throughout the mitotic phase, suggesting they may play an essential function in the cell-cycle regulated condensation of the Drosophila chromosomes. Through search in the genomic database, we also have identified a Drosophila polypeptide, DmMT2, that exhibits high sequence homology to the mammalian dnmt2 and the yeast CpG MTase homolog pmt1. The expression of DmMT2 appears to be developmentally regulated. We discuss the evolutionary and functional implications of the discovery of these two Drosophila proteins related to mammalian CpG MTases.

Amino Acid Sequence↗
PubMed1999

The chitinase PfCHT1 from the human malaria parasite Plasmodium falciparum lacks proenzyme and chitin-binding domains and displays unique substrate preferences.

Within hours after the ingestion of a blood meal, the mosquito midgut epithelium synthesizes a chitinous sac, the peritrophic matrix. Plasmodium ookinetes traverse the peritrophic matrix while escaping the mosquito midgut. Chitinases (EC 3.2.1.14) are critical for parasite invasion of the midgut: the presence of the chitinase inhibitor, allosamidin, in an infectious blood meal prevents oocyst development. A chitinase gene, PgCHT1, recently has been identified in the avian malaria parasite P. gallinaceum. We used the sequence of PgCHT1 to identify a P. falciparum chitinase gene, PfCHT1, in the P. falciparum genome database. PfCHT1 differs from PgCHT1 in that the P. falciparum gene lacks proenzyme and chitin-binding domains. PfCHT1 was expressed as an active recombinant enzyme in Escherichia coli. PfCHT1 shares with PgCHT1 a substrate preference unique to Plasmodium chitinases: the enzymes cleave tri- and tetramers of GlcNAc from penta- and hexameric oligomers and are unable to cleave smaller native chitin oligosaccharides. The pH activity profile of PfCHT1 and its IC(50) (40 nM) to allosamidin are distinct from endochitinase activities secreted by P. gallinaceum ookinetes. Homology modeling predicts that PgCHT1 has a novel pocket in the catalytic active site that PfCHT1 lacks, which may explain the differential sensitivity of PfCHT1 and PgCHT1 to allosamidin. PfCHT1 may be the ortholog of a second, as yet unidentified, chitinase gene of P. gallinaceum. These results may allow us to develop novel strategies of blocking human malaria transmission based on interfering with P. falciparum chitinase.

Acetylglucosamine↗
PubMed2000

A family of peptidoglycan recognition proteins in the fruit fly Drosophila melanogaster.

Peptidoglycans from bacterial cell walls trigger immune responses in insects and mammals. A peptidoglycan recognition protein, PGRP, has been cloned from moths as well as vertebrates and has been shown to participate in peptidoglycan-mediated activation of prophenoloxidase in the silk moth. Here we report that Drosophila expresses 12 PGRP genes, distributed in 8 chromosomal loci on the 3 major chromosomes. By analyzing cDNA clones and genomic databases, we grouped them into two classes: PGRP-SA, SB1, SB2, SC1A, SC1B, SC2, and SD, with short transcripts and short 5'-untranslated regions; and PGRP-LA, LB, LC, LD, and LE, with long transcripts and long 5'-untranslated regions. The predicted structures indicate that the first group encodes extracellular proteins and the second group, intracellular and membrane-spanning proteins. Most PGRP genes are expressed in all postembryonic stages. Peptidoglycan injections strongly induce five of the genes. Transcripts from the different PGRP genes were found in immune competent organs such as fat body, gut, and hemocytes. We demonstrate that at least PGRP-SA and SC1B can bind peptidoglycan, and a function in immunity is likely for this family.

Amino Acid Sequence↗
PubMed1999

Genetic analysis of glutathione peroxidase in oxidative stress response of Saccharomyces cerevisiae.

Three glutathione peroxidase homologs (YKL026C, YBR244W, and YIR037W/HYR1) were found in the Saccharomyces Genome Database. We named them GPX1, GPX2, and GPX3, respectively, and we investigated the function of each gene product. The gpx3Delta mutant was hypersensitive to peroxides, whereas null mutants of the GPX1 and GPX2 did not show any obvious phenotypes. Glutathione peroxidase activity decreased approximately 57 and 93% in the gpx3Delta and gpx1Delta/gpx2Delta/gpx3Delta mutants, respectively, compared with that of wild type. Expression of the GPX3 gene was not induced by any stresses tested, whereas that of the GPX1 gene was induced by glucose starvation. The GPX2 gene expression was induced by oxidative stress, which was dependent upon the Yap1p. The TSA1 (thiol-specific antioxidant) gene encodes thioredoxin peroxidase that can reduce peroxides by using thioredoxin as a reducing power. Disruption of the TSA1 gene enhanced the basal expression level of the Yap1p target genes such as GSH1, GLR1, and GPX2 and that resulted in increases of total glutathione level and activities of glutathione reductase and glutathione peroxidase. However, expression of the TSA1 gene did not increase in the gpx1Delta/gpx2Delta/gpx3Delta mutant. Therefore, de novo synthesis and recycling of glutathione were increased in the tsa1Delta mutant to maintain the catalytic cycle of glutathione peroxidase reaction efficiently as a backup system for thioredoxin peroxidase.

Amino Acid Sequence↗
PubMed2000

Regulation of APG14 expression by the GATA-type transcription factor Gln3p.

Gln3p is a nitrogen catabolite repression-sensitive GATA-type transcription factor. Its nuclear accumulation was recently shown to be under the control of TOR signaling. Gln3p normally resides in the cytoplasm. When cells are starved from nitrogen nutrients or treated with rapamycin, however, Gln3p becomes translocated into the nucleus, thereby activating the expression of genes involved in nitrogen utilization and transport. To identify other genes under the control of Gln3p, we searched for the Gln3p-binding GATAA motifs within 500 base pairs of the promoter sequences upstream of the yeast open reading frames in the Saccharomyces Genome Database. APG14, a gene essential for autophagy, was found to have the most GATAA motifs. We show that nitrogen starvation or rapamycin treatment rapidly causes a more than 20-fold induction of APG14. The expression of APG14 is dependent on Gln3p; deletion of Gln3p severely reduced its induction by rapamycin, whereas depletion of Ure2p caused its constitutive expression. However, overexpression of APG14 led to only a slight increase in autophagy in nitrogen-rich medium. Therefore, these results define a signaling cascade leading to the expression of APG14 in response to the availability of nitrogen nutrients and suggest that the regulated expression of APG14 contributes to but is not sufficient for the control of autophagy.

5' Untranslated Regions↗
PubMed2003

Oral fibroblast expression of wound-inducible transcript 3.0 (wit3.0) accelerates the collagen gel contraction in vitro.

Wounds of the oral mucosa show faster closure with less scar formation than skin wounds in other areas. A differentially expressed cDNA, wound-inducible transcript 3.0 (wit3.0), was isolated from oral mucosal wound in rats (Sukotjo, C., Abanmy, A. A., Ogawa, T., and Nishimura, I. (2002) J. Dent. Res. 81, 229-235). The purpose of this study was to characterize the wit3.0 gene structure and the function of its deduced peptide. Human and rat genome databases revealed that the gene for wit3.0 was located in human chromosome 12p11.23 and rat chromosome 4q44. Its human and rat gene structures were well conserved, composed of 7 exons spread over 20 kb. Exon 5 was alternatively spliced generating two transcripts encoding deduced peptides of 215 and 253 amino acids (wit3.0 alpha and wit3.0 beta, respectively). The protein families data base of alignments (Pfam) analysis suggested the wit3.0 peptide sequence shared similarity with a portion of the myosin II coiled-coil domain consensus sequence. Fibroblasts isolated from the rat oral wound up-regulated wit3.0 expression and exhibited greater ability to contract collagen gel in vitro than fibroblasts isolated from untreated oral mucosa/gingiva. NIH3T3 and rat oral fibroblasts transfected with expression vector containing the coding sequences of wit3.0 alpha or wit3.0 beta increased in vitro collagen gel contraction. When treated with TGF beta-1, NIH3T3 fibroblast expression of wit3.0 showed no significant change, whereas alpha smooth muscle actin was increased in a dose-dependent manner. These data suggest that there may be a novel wound healing pathway involving wit3.0 underlying the favorable early wound closure characteristics of oral mucosa.

Actins↗
PubMed2006

Multifunctional glyceraldehyde-3-phosphate dehydrogenase of Streptococcus pyogenes is essential for evasion from neutrophils.

Streptococcus pyogenes is an important pathogen that causes pharyngitis, sepsis, and rheumatic fever. Cell-associated streptococcal C5a peptidase (ScpA) protects S. pyogenes from phagocytosis and has been suggested to interrupt host defenses by enzymatically cleaving complement C5a, a major factor in the accumulation of neutrophils at sites of infection. How S. pyogenes recognizes and binds to C5a, however, is unclear. We detected a C5a-binding protein in 8 M urea extracts of S. pyogenes by ligand blotting using biotinylated C5a. Searching of genome databases showed that the C5a-binding protein is identical to the streptococcal plasmin receptor (Plr), also known as streptococcal surface dehydrogenase (SDH) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). In the present study we identified a novel function of this multifunctional protein. Western blotting and immunofluorescence microscopy with anti-Plr/SDH/GAPDH showed that Plr/SDH/GAPDH is located on the bacterial surface and released into the culture supernatant. Next, we examined whether the streptococcal Plr/SDH/GAPDH inhibits the biological effects of C5a on human neutrophils. We found that soluble Plr/SDH/GAPDH inhibits C5a-activated chemotaxis and H2O2 production. Furthermore, our results suggested that soluble Plr/SDH/GAPDH captures C5a, inhibiting its chemotactic function. Also, cell-associated Plr/SDH/GAPDH and ScpA were both necessary for the cleavage of C5a on the bacterial surface. Together, these results indicate that the multifunctional protein Plr/SDH/GAPDH has additional functions that help S. pyogenes escape detection by the host immune system.

Animals↗