Identification of Proteins Associated with the Formation of Oral Biofilms

ABSTRACT Objective: To identify proteins associated with the formation of Streptococcus gordonii and Fusobacterium nucleatum biofilms. Material and Methods: Biofilms composed of two bacterial species, S. gordonii and F. nucleatum, were cultured for 1, 4, 7, and 10 days. The presence of both species was confirmed via amplification of the srtA and radD genes using real-time PCR. The concentrations of proteins associated with the biofilms and individual species were quantified using Western blotting. Results: The protein profiles of S. gordonii and F. nucleatum from individual cultures determined using one-dimensional electrophoresis revealed proteins found in S. gordonii and in F. nucleatum. Ct and reciprocal Ct values were determined for the exposed S. gordonii and F. nucleatum biofilms. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) protein was detected in biofilms and F. nucleatum, whereas HSP40 protein was present only in biofilms after 7 and 10 days of formation. Conclusion: HSP40 was detected only in the formed biofilms; thus, HSP40 is an essential proteins for adhesion.

Proteomic identification and functional characterization of MYH9, Hsc70, and DNAJA1 as novel substrates of HDAC6 deacetylase activity

Histone deacetylase 6 (HDAC6), a predominantly cytoplasmic protein deacetylase, participates in a wide range of cellular processes through its deacetylase activity. However, the diverse functions of HDAC6 cannot be fully elucidated with its known substrates. In an attempt to explore the substrate diversity of HDAC6, we performed quantitative proteomic analyses to monitor changes in the abundance of protein lysine acetylation in response to HDAC6 deficiency. We identified 107 proteins with elevated acetylation in the liver of HDAC6 knockout mice. Three cytoplasmic proteins, including myosin heavy chain 9 (MYH9), heat shock cognate protein 70 (Hsc70), and dnaJ homolog subfamily A member 1 (DNAJA1), were verified to interact with HDAC6. The acetylation levels of these proteins were negatively regulated by HDAC6 both in the mouse liver and in cultured cells. Functional studies reveal that HDAC6-mediated deacetylation modulates the actin-binding ability of MYH9 and the interaction between Hsc70 and DNAJA1. These findings consolidate the notion that HDAC6 serves as a critical regulator of protein acetylation with the capability of coordinating various cellular functions.

Effect of dexamethasone on unfolded protein response genes (MTJ1, Grp78, Grp94, CHOP, HMOX-1) in HEp2 cell line.

The endoplasmic reticulum (ER) is related to the various signal routes that are activated in unfolded protein response (UPR). The Grp78, Grp94, CHOP, MTJ1 and HMOX1 genes expressions demonstrate UPR activity. In this study, we investigated the UPR gene expressions in larynx epidermoid carcinoma (HEp2) to which dexamethasone (dex) was applied. HEp2 cells were administered for 48 h with different combinations using 0.1 μM and 1 μM dex, 1 mM phenyl butyric acid (PBA) and 100 ng/ml lipopolysaccharide (LPS). The Grp78, Grp94, CHOP, MTJ1 and HMOX1 genes expression was determined using quantitative RT-PCR. The Grp78, MTJ1 and HMOX1 gene expression increased with the administration of 1 µM dex. CHOP expression, on the other hand, decreased with 0.1 µM dex. When dex was combined with LPS, nearly all gene expressions decreased. The increase in Grp78, Grp94, HMOX1 and MTJ1 gene expression was greater in groups in which dex was administered in combination with PBA than in groups in which dex was administered alone. Dex in low dose (0.1 μM) caused a decrease in CHOP expression in HEp2 cells and an increase in Grp78 expression, in particular. The changes in UPR genes expressions may lead to the extended survival of the cells.

Eukaryotic DNAJ/K Database: A Comprehensive Phylogenomic Analysis Platform for the DNAJ/K Family

Proteins in DNAJ/K families are ubiquitous, from prokaryotes to eukaryotes, and function as molecular chaperones. For systematic phylogenomics of the DNAJ/K families, we developed the Eukaryotic DNAJ/K Database (EDD). A total of 12,908 DNAJs and 4,886 DNAKs were identified from 339 eukaryotic genomes in the EDD. Kingdom-wide comparison of DNAJ/K families provides new insights on the evolutionary relationship within these families. Empowered by 'class', 'cluster', and 'taxonomy' browsers and the 'favorite' function, the EDD provides a versatile platform for comparative genomic analyses of DNAJ/K families.

Construction of pQE/Dnajb13 recombinant plasmid and the protein expression / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct pQE/Dnajb13 recombinant vector and induce the expression of the fusion protein.</p><p><b>METHODS</b>The open reading frame (ORF) of Dnajb13 gene was amplified from mouse testis cDNA library by PCR. The products were digested by SacI and SalI and subcloned into pQE vector. After identification by DNA sequence analysis, the recombinant plasmids were transformed into competent E.coli M15 cells. The His/Dnajb13 fusion protein was expressed with IPTG induction and purified with Ni(2+) affinity chromatography. Western blotting was used to detect Dnajb13 expression.</p><p><b>RESULTS</b>The recombinant vector pQE/Dnajb13 was successfully constructed. His/Dnajb13 fusion protein was expressed abundantly at 4 h after IPTG induction, and Western blot analysis demonstrated the presence of Dnajb13 expression in E.coli M15.</p><p><b>CONCLUSIONS</b>We have successfully constructed pQE/Dnajb13 recombinant vector, which may facilitate further investigation of the role of Dnajb13 in spermatogenesis.</p>

Interaction of Hsp40 with influenza virus M2 protein: implications for PKR signaling pathway

Influenza virus contains three integral membrane proteins: haemagglutinin, neuraminidase, and matrix protein (M1 and M2). Among them, M2 protein functions as an ion channel, important for virus uncoating in endosomes of virus-infected cells and essential for virus replication. In an effort to explore potential new functions of M2 in the virus life cycle, we used yeast two-hybrid system to search for M2-associated cellular proteins. One of the positive clones was identified as human Hsp40/Hdj1, a DnaJ/Hsp40 family protein. Here, we report that both BM2 (M2 of influenza B virus) and A/M2 (M2 of influenza A virus) interacted with Hsp40 in vitro and in vivo. The region of M2-Hsp40 interaction has been mapped to the CTD1 domain of Hsp40. Hsp40 has been reported to be a regulator of PKR signaling pathway by interacting with p58(IPK) that is a cellular inhibitor of PKR. PKR is a crucial component of the host defense response against virus infection. We therefore attempted to understand the relationship among M2, Hsp40 and p58(IPK) by further experimentation. The results demonstrated that both A/M2 and BM2 are able to bind to p58(IPK) in vitro and in vivo and enhance PKR autophosphorylation probably via forming a stable complex with Hsp40 and P58(IPK), and consequently induce cell death. These results suggest that influenza virus M2 protein is involved in p58(IPK) mediated PKR regulation during influenza virus infection, therefore affecting infected-cell life cycle and virus replication.

Preparation of the anti-HLJ1 monoclonal antibodies and establishment of method for detection of the antigen / 生物工程学报

Monoclonal antibodies (McAbs) against human liver DnaJ-like protein (HLJ1) was produced by using lymphocyte-hybridoma technique and then one method for the detection of HLJ1 antigen was established. Two hybridoma cell lines which stably secreted monoclonal antibodies against HLJ1 were generated and named for A4C7 and C4C8. Subtypes of the two McAbs were both IgG1, and the antibodies showed high titer and good specificity. Using the prepared monoclonal antibody, human embryonic liver tissues were examined by immunohistochemistry. The results indicated that HLJ1 located in the cytoplasm of the human embryonic liver cell. A double antibodies sandwich ELISA was established by using C4C8 and HRP labeled A4C7. This assay had good specificity, and the lowest detection limit was 7.5 ng/mL and the linear range was 7.5-750 ng/mL. In conclusion, an immunohistochemistry method and a sensitive sandwich ELISA were established for the detection of HLJ1 protein.

Establishment and application of a RT-PCR system for quantifying mRNA of 4 hsp genes in human cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To establish a RT-PCR system for detecting mRNA expression level of 4 hsp genes in human cells.</p><p><b>METHODS</b>RT-PCR system was established with gene cloning, gene recombination, in vitro transcription and RT-PCR techniques; The detection of expression level of 4 hsp genes in SW13 cell was carried out with this system.</p><p><b>RESULTS</b>In SW13 cell, hsp70 and hsp90 alpha were typical heat shock induced genes, while hsp60 and hsp90 beta were efficiently expressed and further induced by heat-shock to various extent.</p><p><b>CONCLUSIONS</b>In our hands novel RT-PCR system can be used to detect mRNA expression level of 4 human hsp genes.</p>