Polymorphisms in glutathione S-transferase M1 and T1 (GSTM1 and GSTT1) in the indigenous and the nonresident population of the Kemerovo region

GSTM1 and GSTT1 gene polymorphisms were studied in Shorians, Teleuts, and Caucasians of the Kemerovo region. It has been shown that distribution of homozygous deletions in the examined groups is significantly heterogeneous. The frequency of deletion genotypes and combinations of deletion in these genes was lower in Shorians and, Teleuts than in Caucasians.     

Role of the ASK1-SEK1-JNK1-HIPK1 signal in Daxx trafficking and ASK1 oligomerization

Overexpression of JNK binding domain inhibited glucose deprivation-induced JNK1 activation, relocalization of Daxx from the nucleus to the cytoplasm, and apoptosis signal-regulating kinase 1 (ASK1) oligomerization in human prostate adenocarcinoma DU-145 cells. However, SB203580, a p38 inhibitor, did not prevent relocalization of Daxx and oligomerization of ASK1 during glucose deprivation. Studies from in vivo labeling and immune complex kinase assay demonstrated that phosphorylation of Daxx occurred during glucose deprivation, and its phosphorylation was mediated through the ASK1-SEK1-JNK1-HIPK1 signal transduction pathway. Data from immunofluorescence staining and protein interaction assay suggest that phosphorylated Daxx may be translocated to the cytoplasm, bind to ASK1, and subsequently lead to ASK1 oligomerization. Mutation of Daxx Ser667 to Ala results in suppression of Daxx relocalization during glucose deprivation, suggesting that Ser667 residue plays an important role in the relocalization of Daxx. Unlike wild-type Daxx, a Daxx deletion mutant (amino acids 501-625) mainly localized to the cytoplasm, where it associated with ASK1, activated JNK1, and induced ASK1 oligomerization without glucose deprivation. Taken together, these results show that glucose deprivation activates the ASK1-SEK1-JNK1-HIPK1 pathway, and the activated HIPK1 is probably involved in the relocalization of Daxx from the nucleus to the cytoplasm. The relocalized Daxx may play an important role in glucose deprivation-induced ASK1 oligomerization.     

Nucleic acid binding and unfolding properties of ribosomal protein S1 and the derivatives S1-F1 and m1-S1.

The nucleic acid binding and unwinding properties of wild-type Escherichia coli ribosomal protein S1 have been compared to those of a mutant form and a large trypsin-resistant fragment, both reported recently [J. Mol. Biol. 127, 41-45 (1979) and J. Biol. Chem. 254, 4309-4312 (1979). The mutant (m1-S1) contains 77% and the fragment (S1-F1) 66% of the polypeptide chain length (approximately 600 amino acid residues) of protein S1. The mutant is active in protein synthesis in vitro; the fragment, although retaining one or more of the functional domains of S1, is inactive in protein synthesis. We find that m1-S1 is is almost as effective as S1 in binding to poly(rU), phage MS2 RNA and simian virus 40 (SV40) DNA, and in unfolding poly(rU) and the helical structures present in MS2 RNA and phi X174 viral DNA. S1-F1, however, binds to poly(rU) and denatured SV40 DNA, but not to MS2 RNA. It unfolds neither poly(rU), nor the residual secondary structure of MS2 RNA or phi X174 viral DNA. Thus, there appears to be a correlation between the loss in ability of S1 to unwind RNA and the loss in its ability to function in protein synthesis.     

Deletion of the Pitx1 genomic locus affects mandibular tooth morphogenesis and expression of the Barx1 and Tbx1 genes

Pitx1 is a bicoid-related homeodomain factor that exhibits preferential expression in the developing hindlimb, mandible, pituitary gland and teeth. Pitx1 gene-deleted mice exhibit striking abnormalities in morphogenesis and growth of both hindlimb and mandible, suggesting a proliferative defect in these two structures. Here, we studied the expression and regulation of Pitx1 in both mandible and developing teeth and analyzed tooth morphology, cell proliferation, apoptosis and expression of Pitx2, Barx1 and Tbx1 in dental tissues of Pitx1−/− mouse embryos. Pitx1 expression is restricted to the epithelium of the growing tooth anlagen. Tissue recombination and bead implantation experiments demonstrated that bone morphogenetic protein-4 down-regulates Pitx1 expression in both mandibular mesenchyme and dental epithelium. Deletion of the Pitx1 locus results in micrognathia and abnormal morphology of the mandibular molars. Although Pitx2 expression in teeth of Pitx1−/− embryos is not altered, expression of Barx1 decreased in the mesenchyme of the mandibular molars. Furthermore, Pitx1 deletion results in suppression of Tbx1 expression in dental epithelium. Taken together, these results indicate that independent genetic pathways in mandibular and maxillary processes determine tooth development and morphology.     

Polymorphisms in glutathione S-transferase M1 and T1 (GSTM1 and GSTT1) genes in the indigenous and the nonresident population of the Kemerovo region

GSTM1 and GSTT1 gene polymorphisms were studied in Shorians, Teleuts, and Caucasians of the Kemerovo region. It has been shown that distribution of homozygous deletions in the examined groups is significantly heterogeneous. The frequency of deletion genotypes and combinations of deletion in these genes was lower in Shorians and, Teleuts than in Caucasians.     

Properties of STAT1 and IRF1 enhancers and the influence of SNPs

Background

STAT1 and IRF1 collaborate to induce interferon-γ (IFNγ) stimulated genes (ISGs), but the extent to which they act alone or together is unclear. The effect of single nucleotide polymorphisms (SNPs) on in vivo binding is also largely unknown.

Results

We show that IRF1 binds at proximal or distant ISG sites twice as often as STAT1, increasing to sixfold at the MHC class I locus. STAT1 almost always bound with IRF1, while most IRF1 binding events were isolated. Dual binding sites at remote or proximal enhancers distinguished ISGs that were responsive to IFNγ versus cell-specific resistant ISGs, which showed fewer and mainly single binding events. Surprisingly, inducibility in one cell type predicted ISG-responsiveness in other cells. Several dbSNPs overlapped with STAT1 and IRF1 binding motifs, and we developed methodology to rapidly assess their effects. We show that in silico prediction of SNP effects accurately reflects altered binding both in vitro and in vivo.

Conclusions

These data reveal broad cooperation between STAT1 and IRF1, explain cell type specific differences in ISG-responsiveness, and identify genetic variants that may participate in the pathogenesis of immune disorders.

     

Interaction between RNA1 and the primer precursor in the regulation of Co1E1 replication

The analysis of a large number of independent mutants in the target of one of the inhibitors of pMB1 replication suggests that RNA1 regulates primer formation by base-pairing with the complementary sequence in the primer precursor. We conclude that the number of bases that are involved in the hydrogen bonding responsible for the specificity of the mechanism that controls plasmid replication and incompatibility properties is not much larger than seven. Five of these bases are located in the central loop and two in loop I of the RNA primer cloverleaf structure. Twenty-two single, double or triple mutants, with different nucleotide sequences in these seven bases, maintain an active mechanism of control, though with altered specificity. The efficiency of the inhibition mechanism correlates with the delta G value of the hydrogen bonds between the nucleotides of the two heptamers postulated to be involved in the interaction. The implications of these findings are discussed, and a molecular model of the interaction between RNA1 and the primer precursor is presented.     

Orai1 mediates the interaction between STIM1 and hTRPC1 and regulates the mode of activation of hTRPC1-forming Ca2+ channels

Orai1 and hTRPC1 have been presented as essential components of store-operated channels mediating highly Ca(2+) selective I(CRAC) and relatively Ca(2+) selective I(SOC), respectively. STIM1 has been proposed to communicate the Ca(2+) content of the intracellular Ca(2+) stores to the plasma membrane store-operated Ca(2+) channels. Here we present evidence for the dynamic interaction between endogenously expressed Orai1 and both STIM1 and hTRPC1 regulated by depletion of the intracellular Ca(2+) stores, using the pharmacological tools thapsigargin plus ionomycin, or by the physiological agonist thrombin, independently of extracellular Ca(2+). In addition we report that Orai1 mediates the communication between STIM1 and hTRPC1, which is essential for the mode of activation of hTRPC1-forming Ca(2+) permeable channels. Electrotransjection of cells with anti-Orai1 antibody, directed toward the C-terminal region that mediates the interaction with STIM1, and stabilization of an actin cortical barrier with jasplakinolide prevented the interaction between STIM1 and hTRPC1. Under these conditions hTRPC1 was no longer involved in store-operated calcium entry but in diacylglycerol-activated non-capacitative Ca(2+) entry. These findings support the functional role of the STIM1-Orai1-hTRPC1 complex in the activation of store-operated Ca(2+) entry.     

沉默DEPDC1抑制鼻咽癌细胞HNE-1和CNE-1侵袭迁移

DEPDC1(DEP domain containing 1)是一个新的肿瘤相关基因,在多种恶性肿瘤的发生发展进程中起着重要作用。我们前期工作中在鼻咽癌细胞内沉默了DEPDC1的表达,发现抑制细胞增殖并诱发细胞凋亡。本研究旨在探讨沉默DEPDC1表达后,对鼻咽癌细胞HNE-1和CNE-1侵袭迁移能力的影响及其分子机制。结果显示,siRNA介导DEPDC1表达沉默后,细胞侧向运动能力、侵袭及迁移能力显著降低。qRT-PCR及Western印迹检测发现DEPDC1沉默导致EMT上游关键转录因子Twist1及间质细胞标志分子Vimentin表达显著下调。这些研究表明,鼻咽癌细胞中DEPDC1通过调节Twist1等EMT关键分子的表达在细胞侵袭转移过程中起关键作用。推测DEPDC1在鼻咽癌中高表达可能对于促进其侵袭转移具有重要作用,进而促进肿瘤发生发展,但具体分子机制仍有待更深入研究。     

Identification and functional analysis of the MOC1 interacting protein 1

Rice tillering is one of the most important agronomic traits that determine grain yields.Our previous study has demonstrated that the MONOCULM1 (MOC1) gene is a key component that controls the formation of rice tiller buds.To further elucidate the molecular mechanism of MOC1 involved in the regulation of rice tillering,we performed a yeast-two-hybrid screening to identify MOC1 interacting proteins (MIPs).Here we reported that MIP1 interacted with MOC1 both in vitro and in vivo.The overexpression of MIP1 res...     

Identification and functional analysis of the MOC1 interacting protein 1

Rice tillering is one of the most important agronomic traits that determine grain yields.Our previous study has demonstrated that the MONOCULM1(MOC1)gene is a key component that controls the formation of rice tiller buds.To further elucidate the molecular mechanism of MOC1 involved in the regulation of rice tillering.we performed a yeast-two-hybrid screening to identify MOC1 interacting proteins(MIPs).Here we reported that MIP1 interacted with MOC1 both in vitro and in vivo.The overexpression of MIP1 resulted in enhanced tillering and reduced plant height.In-depth characterization of the context of MIP1 and MOC1 would further our understanding of molecular regulatory mechanisms of rice tillering.     

On the role of IS1 in the formation of hybrids between the bacteriophage P1 and the R plasmid NR1

Summary The genomes of bacteriophage P1 derivatives carrying drug resistance genes derived from an R plasmid NR1 were analysed by restriction cleavage and be DNA-DNA hybridization. Two representatives of a class of oversized P1CmSmSu phages were identified as P1 carrying the entire r-determinant of NR1 together with its two flanking, directly repeated IS1. In one case the r-determinant insertion is carried at the site of the residential IS1 of P1, in the other case it is transposed into another region of the P1 genome. Models postulate that the first type resulted from reciprocal recombination within IS1 elements and that the formation of the second type of P1-R hybrid depended both on IS1 mediated transposition and reciprocal recombination. Plaque forming P1Cm or P1CmSm phages are explained as IS1 mediated deletion derivatives of P1CmSmSu, although an alternative model postulates that sometimes P1Cm phages might result from two consecutive transposition events of only one IS1 without involving reciprocal recombination. Secondary P1 derivatives carrying only one IS1 at the site of the original r-determinant or of Cm insertions into P1 must have been produced by reciprocal recombination between the two IS1 flanking the insertions. An implication from this study, that any genetic material carried adjacent to an IS1 element may undergo passive transposition, is discussed.