Activation and repression functions of an SR splicing regulator depend on exonic versus intronic-binding position

SR proteins and related factors play widespread roles in alternative pre-mRNA splicing and are known to promote splice site recognition through their Arg–Ser-rich effector domains. However, binding of SR regulators to some targets results in repression of splice sites through a distinct mechanism. Here, we investigate how activated and repressed targets of the Drosophila SR regulator Transformer2 elicit its differing effects on splicing. We find that, like activation, repression affects early steps in the recognition of splice sites and spliceosome assembly. Repositioning of regulatory elements reveals that Tra2 complexes that normally repress splicing from intronic positions activate splicing when located in an exon. Protein tethering experiments demonstrate that this position dependence is an intrinsic property of Tra2 and further show that repression and activation are mediated by separate effector domains of this protein. When other Drosophila SR factors (SF2 and Rbp1) that activate splicing from exonic positions were tethered intronically they failed to either activate or repress splicing. Interestingly, both activities of Tra2 favor the exonic identity of the RNA sequences that encompass its binding sites. This suggests a model in which these two opposite functions act in concert to define both the position and extent of alternatively spliced exons

Research advances on Chlamydia trachomatis outer membrane complex protein B

Chlamydia trachomatis is the most common sexually transmitted pathogen. Due to the latency of the symptoms, Chlamydia trachomatis cannot be diagnosed and treated in the early stage, leading to the development of severe chronic disease with complications and sequelae. Outer membrane complex protein B (OmcB) is the second most abundant outer membrane protein in chlamydia. Because of its abundance and powerful immunogenicity during the infection, OmcB has a very promising prospect in the fields of the diagnosis of CT infection and the development of vaccines. This article reviews the structure and localization of OmcB, and the related mechanisms during Chlamydia trachomatis infection

The Chinese TCM industry: Growth, changes, and policies

We analyse the current situation, the performances and geographical distribution and some of the main policies related to TCM industry in Chin

Isolation and Identification Rust Pathogens and the Study of Antioxidant Enzyme Activity and Gene Expression under Rust Infection in Zoysia japonica

The goal of this study was to identify the zoysiagrass rust pathogens and to analyze the differences in rust-resistant and rust-susceptible Zoysia japonica germplasm upon inoculation. Based on the assessment of spore morphology and 18S ribosomal DNA (rDNA) molecular identification, the zoysiagrass rust pathogen was identified as Puccinia zoysiae Diet. The development of mycelium, the rate of spreading, and the timing of spore production were more delayed in the rust-resistant (RR) genotype than the rust-susceptible (RS) genotype. After inoculation, the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) initially decreased, then increased in both the RR and RS genotypes, but the increased enzyme activities were faster in the RR than in the RS genotype. Rust resistance was positively correlated with antioxidant enzyme activity. The observed changes in CAT, POD and APX activity corresponded to their gene expression levels. The results of this study may be utilized in accurately evaluating the damage of rust disease and rust-resistance in zoysiagrass germplasm aimed at breeding the rust-resistant zoysiagrass varieties and improving disease management of zoysiagrass turf

Chlamydial genomic MinD protein does not regulate plasmid-dependent genes like Pgp5

Chlamydia has a unique intracellular developmental cycle, which has hindered the single protein function study of Chlamydia. Recently developed transformation system of Chlamydia has greatly advanced the chlamydial protein's function research and was used to find that a chlamydial plasmid-encoded Pgp5 protein can down-regulate plasmid-dependent genes. It is assumed, that chlamydial genomic MinD protein has a similar function to Pgp5. However, it is unknown whether MinD protein regulates the same plasmid-dependent genes. We replaced pgp5 gene in the shuttle vector pGFP::CM with minD gene of C. trachomatis (CT0582) or C. muridarum (TC0871). The recombinant plasmid was transformed into plasmid-free organisms-CMUT3 and qRT-PCR was used to detect the transcription level of plasmid-encoded and -dependent genes in these pgp5 deficient organisms. As a readout, GlgA, one of the plasmid-regulated gene products was detected by immunofluorescence assay. After recombination, transformation and plaque purification, the stable transformants CT0582R and TC0871R were generated. In these transformants, the plasmid-dependent genes were up-regulated, alike in the pgp5 premature stop mutant and pgp5 replacement with mCherry mutant. GlgA protein level was also increased in all pgp5 mutants, including CT0582R and TC0871R. Thus, our study showed that genomic MinD protein had different function than Pgp5, which was useful for further understanding the chlamydiae

The presence of Chlamydia phage PhiCPG1 capsid protein VP1 genes and antibodies in patients infected with Chlamydia trachomatis

Chlamydia phage PhiCPG1 has been found in Chlamydia caviae in a guinea pig model for inclusion conjunctivitis, raising the possibility that Chlamydia phage is also present in patients infected with C. trachomatis (Ct). In the present study, we assayed for presence of Chlamydia phage capsid protein VP1 genes and antibodies in 84 non-Ct controls and 206 Ct patients using an enzyme-linked immunoassay (ELISA), followed by verification with Western blot. None of the subjects were exposed to an antibiotic treatment or had a C. pneumoniae infection. The VP1 antibody test was positive in both, the ELISA and Western blot assay, in 4 Ct patients. PCR amplification experiments revealed presence of the VP1 gene in 5 Ct patients. The results suggest that Chlamydia phage capsid protein VP1 may exist in some Ct patients