Abstract:The 24p3 of mouse is a member of lipocalin family and it has been implicated in iron transport and apoptosis due to interleukin-3(IL-3) deprivation. Devireddy and colleagues cloned the receptor of 24p3 and further confirmed that the pathway of 24p3-24p3R is a new iron transport approach in Dec 2005. A link between iron internalization mediated by 24p3R and regulation of apoptosis was suggested.

Abstract:Aminoacyl-tRNA synthetases (AARSs) catalyze aminoacylation of their tRNAs for protein biosynthesis. As belong to one of the most ancient and conserved enzyme family their additional functions in mammalian cells were focused recently. Mutations in tyrosyl-tRNA synthetase, glycyl-tRNA synthetase and alanyl-tRNA synthetase from patients and mice models were identified to cause two subtypes of Charcot-Marie-Tooth disease and cerebellar Purkinje cell loss, respectively. These mutations affect different functions of the three enzymes including aminoacylation, editing and unknown functions. These results combined AARSs with neurodegeneration and gave new sights into neuropathy.

Abstract:Aptazymes are a new artificial synzyme, selected from the random oligonucleotide sequence libraries against various of effector molecules. They own the advantages of an aptamer(the receptor site) and the ribozyme (the catalytic active site). Moreover, aptazymes as catalytic molecular beacon provide a new orientation for the quantitative analysis of effector molecules. Aptazymes not only have the application in genomics and proteomics,　but also have potential applications in biosensor and DNA AND gate.

Abstract:Protein is transported to specific subcellular localization after it is synthesized in cells, which is crucial to its function. Inaccurate destination will have great impact on cellular function or even life. Protein subcellular localization, which is one of the important areas in protein function research, is the hot issue in bioinformatics. Databases, analyses and prediction of subcellular localization accelerate the research of protein structure and function.

Abstract:Macrophage migration inhibitory factor (MIF) plays an important role in the regulation of the innate and adaptive immunity and is implicated in inflammation, sepsis and autoimmune disease. Previous works have shown that MIF could induce the expression of many cytokines, such as TNF-α, IL-1β, IL-6 and IL-8 in macrophage. It was reported here that MIF up-regulates the type Ⅱ TNF-α receptor (p75 TNFR) expression at mRNA level in RAW264.7 cell line. When RAW264.7 cells were treated with MIF inhibitor, antibody neutralizing MIF activities or the siRNA specific to MIF receptor CD74, the baseline TNFRⅡ mRNA level was reduced. Using inhibitors specific to Erk, JNK, p38, Src or PKA, it was demonstrated that MIF regulation of TNFRⅡ mRNA expression is mediated by Src and JNK. The up-regulation of the TNF-α type Ⅱ receptor by MIF suggests a mechanism of amplifying inflammatory signals while avoiding side effects of TNF-α, such as apoptosis or cytotoxicity during macrophage activation.

Abstract:The peptidyl-prolyl imide bond cis/trans isomerization of Xaa-Pro motif in the peptide and protein plays an important role to influence their conformation and function. Here, a series of model peptides including phosphorylated and its unphosphorylated counterparts were designed and synthesized. Preliminary ¹H NMR experiments and molecular dynamics (MD) simulation were used to analyze the peptidyl-prolyl cis/trans imide bond isomerization. The data indicated that the side-chain O-phosphorylation of the Xaa residues preceding proline affected evidently the isomerization and thereby regulated the peptides conformations. The charges of the phosphate moiety as well as their steric effects might be the driving force for the conformational changes of these phosphopeptides. Moreover, the obtained most stable multiple configurations and their statistic cis/trans concentration distribution in MD simulation were basically consistent with the NMR experiments, which demonstrated that phosphorylation increased the cis conformation of the peptide and the maximum cis ratio is given while the phosphate group has no negative charge.

Abstract:Nodal signals play important roles in mesendoderm induction, establishment of left-right asymmetry and anteroposterior patterning of the neuroectoderm during vertebrate embryogenesis. It is aimed at identifying Nodal-regulated genes in zebrafish embryos, particularly those encoding transcription factors. A (Affymetrix) genechip analysis was performed using RNAs derived from embryos injected with squint mRNA, MZoep mutant embryos that are deficient in Nodal signaling, and wildtype embryos at the 30% epiboly stage. Transcripts (genes) with at least two-fold changes in expression level between wildtype and the other samples were identified. In squint mRNA-injected embryos, 265 transcripts show an increased expression level and 111 have a decreased expression level; in MZoep embryos, the expression of 1 495 transcripts increases while 550 transcripts express at a decreased level. Furthermore, overexpression of squint causes increased expression of 26 and decreased expression of 11 annotated transcription factor genes; in MZoep embryos, the number of transcription factor genes showing an increase and decrease of expression are 69 and 30, respectively. These results would provide useful information for further studying mechanisms and biological functions of Nodal signal transduction.

Abstract:A causal relationship between inflammation and cancer has long been suspected. It was demonstrated the presence of leukocytes in malignant tissues and claimed that tumors arise from regions of chronic inflammation. Hepatocellular carcinoma (HCC), the third leading cause of cancer mortality worldwide, commonly develops in the background of chronic hepatitis. The molecular and cellular mechanisms linking chronic inflammation to tumorigenesis remain largely unresolved. To investigate the roles of TNF-α on the formation and development of HCC, cell cycle, cyclin D1 and cyclin E was measured after treatment with TNF-α. Meanwhile, phosphorylated ERK1/2 and NF-κB activation were also assessed. After blocking the activation of ERK1/2 and NF-κB, the distribution of cell cycle and cyclin D1 expression was measured. It was found that G0/G1-to-S-phase transition was accelerated in human hepatic cell line L-02 treated by TNF-α treatment. Also TNF-α treatment can induce cyclin D1 expression in dose dependent but not cyclin E expression. Simultaneously, inhibition of NF-κB but not inhibition of ERK1/2 caused TNF-α-induced cell cycle arrest at G0/G1 and the increased levels of cyclin D1 expression. These result suggest that TNF-α promotes cell cycle progression by increasing expression of cyclin D1 due to NF-κB activation in human hepatic cell line L-02. Therefore, it enhances formation and progression of hepatocellular carcinoma. Suppression of a major signalling factor of inflammation, such as NF-κB or TNF-α, could thus be a tool to prolong the premalignant phase and inhibit tumour progression in chronic inflammatory diseases with high cancer risk.

Abstract:ATP-binding cassette transporter A1 (ABCA1) plays a crucial role in apoA-Ⅰ binding activity and promotes cellular cholesterol efflux. In order to investigate the effect of interaction between apoA-Ⅰ and ABCA1 on atherosclerosis, and to discover the mechanism of interaction between apoA-Ⅰ and ABCA1, THP-1 cells were induced to become the macrophages by the phorbol. Then THP-1 macrophages were induced to the foam cells by ox-LDL. Treatment of THP-1 macrophage derived foam cells with apoA-Ⅰ, forskolin (FRK, an adenyl cyclase activator), and SQ-22536 (an adenyl cyclase inhibitor) for long periods of time (24 h). In addition, THP-1 macrophage derived foam cells were treated with increasing amounts of FRK (0, 10, 20, 40 and 80 μmol/L) and treated with FRK for increasing time(0, 6, 12 and 24 h). Cholesterol efflux, ABCA1 mRNA and protein level were determined by FJ-2107P type liquid scintillator, reverse transcriptase-polymerase chain reaction and Western blotting, respectively. Cellular lipid accumulation was determined by Oil Red O staining and high performance liquid chromatography analysis. The cholesterol efflux of control group, apoA-Ⅰ group, FRK group, apoA-Ⅰ+ FRK group and apoA-Ⅰ+SQ-22536 group was (8.64 ± 0.83)%, (9.8 ± 0.93)%, (10.15 ± 0.98)%, (11.72 ± 1.1)%, and (6.77 ± 0.7)%, respectively. ApoA-Ⅰ resulted in a 26.7% increase in protein expression of ABCA1, and a 14.0% increase in cholesterol efflux from THP-1 macrophage derived foam cells (P < 0.05). The similar results have been observed in foam cells treated with FRK. ApoA-Ⅰ, in combination with FRK, contributed to a much larger increase in protein expression of ABCA1 (80%, P < 0.05) and cholesterol efflux (36%, P < 0.05) from THP-1 macrophage derived foam cells. In converse, treatment THP-1 macrophage derived foam cells with apoA-Ⅰ and SQ-22536 markedly down-regulated protein expression of ABCA1 (26.7%, P < 0.05) and decreased cholesterol efflux (22.1%, P < 0.05). However, apoA-Ⅰ, FRK and SQ-22536 alone or combination did not influence mRNA expression of ABCA1. These findings suggest that apoA-Ⅰ may stabilize ABCA1 protein, and then increase cellular cholesterol efflux through PKA signaling.

Abstract:Many kinds of small heat shock proteins (sHSPs) are able to prevent protein aggregation in stress, which show the ATP independent chaperone-like activity. The smallest protein HSP12.1 in sHSP family of the nematode Caenorhabditis elegans exhibits chaperone-like activities in vitro. It prevents protein aggregation in a certain extent when use insulin, ADH and lysozyme as the substrates, though it is not as efficient as the typical chaperones (such as HSP16.1 in C. elegans). By contrast, the other three sHSP12s (HSP12.2, HSP12.3 and HSP12.6), which have similar molecular masses and primary structure, appear devoid of in vitro chaperone-like activities. In addition, overexpressing HSP12.1 enhances cell thermotolerance of Escherichia coli. The survival rate of the HSP12.1 overexpressed cells is 4-fold higher than the control, yet whether it does the same function in C. elegans is still unknown. Results indicate that C-terminal region is not necessary for the chaperone-like activity of sHSPs, for HSP12.1 terminates a short C-terminal tail. N-terminal domain may play a relatively important role in the exhibition of chaperone-like activities, while α-crystalline domain may also involve in this function.

Abstract:Correlation coefficient between the expression levels of two genes plays an important role in the inference of their relationship in microarray experiments. Gene expression data before normalization often present high correlation coefficients among a large proportion of genes. Some of these high correlations are caused by changes in gene expression levels. However, most of them are caused by systematic errors. It is intended to eliminate superficial high correlations induced by systematic errors and at the same time, preserve high correlation coefficients stem from gene interactions. Although there are a number of comparisons among different normalization methods, less work focused on evaluating the effect of normalization procedures on correlation coefficients among genes and which method does the best in restoring gene correlation structure. Some gene expression data were simulated with reference to real world gene expression data. With the help of these simulated data, it was determined which normalization method does the best in restoring gene correlation structure. In addition, it was shown that the simulated data and the real world data have the same gene correlation structure, so the conclusion drawn from simulated data can be applied to the real world. For 5 normalization methods compared here, it can be concluded that the loess method is the most appropriate one in eliminating superficial correlation coefficients.

Abstract:The fused gene (TAT PTD-Ngb) which included nine amine acid transactivator of transcription (TAT) protein transduction domain (RKKRRQRRR) of HIV-1 and neuroglobin gene was amplified by RT-PCR from rat brain RNA and cloned into the expression plasmid pET28b. The recombinant plasmid pET-PN was transformed into the E.coli. BL21(DE3)plysS, which was induced with IPTG (0.4 mmol/L) to express TAT PTD-Ngb fusion protein. Ni-NTA resin was used to purify the product, which was identified by SDS-PAGE and Western blot subsequently. After being purified and desalted, the biological activity of TAT PTD-Ngb was deteced in primary cultured cortical neurons. The results showed that TAT PTD-Ngb could transduced into cortical neurons, increase cell viability under hypoxia and attenuate apoptosis induced by hypoxia. The present study provides a clue for the research of neuroglobin and seems to provide a protein therapy strategy for CNS diseases,especially in cerebrovascular diseases and neurodegenerative diseases.

Abstract:Temporal and spatial expressions of β-catenin investigated in the hair follicle and epidermis of the hoof periphery in bovine embryonic development. IHC (immunohistochemical method) was applied to qualitatively detect the temporal and spatial expressions of β-catenin. β-catenin was detected in suprabasal, epidermal basal layer, placode, hair bud in early phase(E68～93),and expressed strongly in epidermal basal layer, placode, and hair bud, in suprabasal expressed less strongly; in metaphase(E94～184), β-catenin was detected in epidermis, hair peg, and in suprabasal, epidermal basal layer, hair follicle bulge, inner root sheath, outer root sheath, follicular infundibulum expressed less strongly; in late phase(E184～225), β-catenin expressed weakly in epidermal basal layers, while expressed strongly in epidermal keratinocytes. The result suggested that β-catenin plays an important role in hair follicle morphogenesis in the periphery of bovine hoof in bovine embryos.

Abstract:A systematic analysis of the typeⅢ secretion genes of Aeromonas hydrophila strain AH-1 by constructing ahyR and ahyI mutant revealed that they are under quorum-sensing control. This observation was supported by the down-regulation of the TTSS genes in the presence of lacZ-TTSS gene promoter and the corresponding advanced secretion of AexT in ahyI mutant.

Abstract:p21-Activated kinases including p21-activated kinase 2 contributed to the regulation of actin cytoskeleton and cell dynamics. In order to investigate the function of PAK2 on the maturation of Xenopus oocyte, PAK2-NT(PAK2-N-terminal,PAK2-NT) and PAK2-NTm (PAK2-N-terminal mutation) mRNA were microinjected into Xenopus oocyte respectively. Under fluorescent microscopy germinal vesicle breakdown was observed during cytokinesis. To further observe the relationship of oocyte cytokinesis, polar body formation and Cdc42 activity, confocal microscopy with time-lapse was employed . As a result, occurrences of germinal vesicle breakdown in oocytes were similar to those oocytes injected with PAK2-NT mRNA or injected with PAK2-NTm mRNA,but no cytokinesis and polar body formation were observed in oocytes injected with PAK2-NT mRNA or PAK2-NTm mRNA. These results indicated that PAK2 involved in Xenopus oocytes cytokinesis and polar body formation independent of Cdc42 activity.

Abstract:A novel polarized light reflective imaging method using rotating linearly polarized light was demonstrated. By varying the incident and detection polarization angles in a fixed increments, a series of images corresponding to different combinations of incident and detection polarizations are recorded. Intensity difference corresponding to orthogonal detection polarizations are calculated pixel by pixel as a function of incident and detection polarization angle and fitted to an empirical formula. The fittings result in a set of parameters. Using various tissue samples and intralipid as phantom, the correlation between these parameters and the optical characters of the sample, such as scattering coefficient, anisotropy and orientation of macro structure was demonstrated. Images based on theses parameters may find clinical applications in diagnosis of skin diseases or assessment of skin damages.