Nucleotide sequences of the D-loop region of human mitochondrial DNA from four Yunnan nationalities, Dai, Wa, Lahu, and Tibetan, were analyzed. Based on a comparison of 563-bp sequences in 99 people, 66 different sequence types were observed. Of these, 64 were unique to their respective populations, whereas only 2 types were shared between the Lahu and Wa nationalities. The D-loop sequence variation and phylogenetic analysis suggested that the 99 mtDNA lineages were classified into eight clusters in the phylogenetic tree. All lineages that had a 9-bp deletion in the COII/tRNA Lys intergenic region appeared in one cluster in the D-loop tree, suggesting a single event of the deletion in the Yunnan nationalities studied. Genetic distances, based on net nucleotide diversities between populations including Han Chinese and mainland Japanese, revealed that the Dai, Wa, Lahu, and Han Chinese are closely related to each other, while Tibetan and mainland Japanese formed a single cluster. The bootstrap probability of separation between the Dai-Wa-Lahu-Chinese clade and the Tibetan-Japanese clade was 99%, indicating that there are at least two different origins among minority groups in Yunnan province. Although the genetic distance between Tibetan and Japanese within the clade is rather long, the results may shed light on the origins of mainland Japanese.

The RNA-dependent RNA polymerase (RdRp) of influenza A virus is a heterotrimeric complex composed of the PB1, PB2, and PA subunits. The interplay between host factors and the three subunits of the RdRp is critical to enable viral RNA synthesis to occur in the nuclei of infected cells. In this study, we newly identified host factor DnaJA1, a member of the type I DnaJ/Hsp40 family, acting as a positive regulator for influenza virus replication. We found that DnaJA1 associates with the bPB2 and PA subunits and enhances viral RNA synthesis both in vivo and in vitro. Moreover, DnaJA1 could be translocated from cytoplasm into the nucleus upon influenza virus infection. The translocation of DnaJA1 is specifically accompanied by PB1-PA nuclear import. Interestingly, we observed that the effect of DnaJA1 on viral RNA synthesis is mainly dependent on its C-terminal substratebinding domain and not on its typical J domain, while the J domain normally mediates the Hsp70-DnaJ interaction required for regulating Hsp70 ATPase activity. Therefore, we propose that DnaJA1 is co-opted by the influenza A virus to enter the nucleus and to enhance its RNA polymerase activity in an Hsp70 cochaperone-independent manner. IMPORTANCEThe interplay between host factors and influenza virus RNA polymerase plays a critical role in determining virus pathogenicity and host adaptation. In this study, we newly identified a host protein, DnaJA1/Hsp40, that is co-opted by influenza A virus RNA polymerase to enhance its viral RNA synthesis in the nuclei of infected cells. We found that DnaJA1 associates with both PB2 and PA subunits and translocates into the nucleus along with the nuclear import of the PB1-PA dimer during influenza virus replication. Interestingly, the effect of DnaJA1 is mainly dependent on its C-terminal substrate-binding domain and not on its typical J domain, which is required for its Hsp70 cochaperone function. To our knowledge, this is the first report on a member of the Hsp40s that is specifically involved in regulating influenza virus RNA polymerase. Targeting the interactions between polymerase subunits and DnaJA1 may provide a novel strategy to develop antiviral drugs.

Background: Trichophyton rubrum is the most common dermatophyte causing fungal skin infections in humans. Asexual sporulation is an important means of propagation for T. rubrum, and conidia produced by this way are thought to be the primary cause of human infections. Despite their importance in pathogenesis, the conidia of T. rubrum remain understudied. We intend to intensively investigate the proteome of dormant T. rubrum conidia to characterize its molecular and cellular features and to enhance the development of novel therapeutic strategies.

BackgroundDermatophytes, the most common cause of fungal infections, affect millions of individuals worldwide. They pose a major threat to public health because of the severity and longevity of infections caused by dermatophytes and their refractivity to therapy. Trichophyton rubrum (T. rubrum), the most common dermatophyte species, is a promising model organism for dermatophyte research. Post-translational modifications (PTMs) have been shown to be essential for many biological processes, particularly in the regulation of key cellular processes that contribute to pathogenicity. Although PTMs have important roles, little is known about their roles in T. rubrum and other dermatophytes. Succinylation is a new PTM that has recently been identified. In this study, we assessed the proteome-wide succinylation profile of T. rubrum. This study sought to systematically identify the succinylated sites and proteins in T. rubrum and to reveal the roles of succinylated proteins in various cellular processes as well as the differences in the succinylation profiles in different growth stages of the T. rubrum life cycle.ResultsA total of 569 succinylated lysine sites were identified in 284 proteins. These succinylated proteins are involved in various cellular processes, such as metabolism, translation and epigenetic regulation. Additionally, 24 proteins related to pathogenicity were found to be succinylated. Comparison of the succinylome at the conidia and mycelia stages revealed that most of the succinylated proteins and sites were growth-stage specific. In addition, the succinylation modifications on histone and ribosomal proteins were significantly different between these two growth stages. Moreover, the sequence features surrounding the succinylated sites were different in the two stages, thus indicating the specific recognition of succinyltransferases in each growth phase.ConclusionsIn this study, we explored the first T. rubrum succinylome, which is also the first PTM analysis of dermatophytes reported to date. These results revealed the major roles of the succinylated proteins involved in T. rubrum and the differences in the succinylomes between the two major growth stages. These findings should improve understanding of the physiological and pathogenic properties of dermatophytes and facilitate future development of novel drugs and therapeutics for treating superficial fungal infections.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3977-y) contains supplementary material, which is available to authorized users.

Shigella flexneri is the causative agent of most shigellosis cases in developing countries. We used different proteolytic enzymes to selectively shave the protruding proteins on the surface of purified bacterial membrane sheets or vesicles, and recovered peptides were subsequently identified using 2-D LC-MS/MS. As a result, a total of 666 proteins were unambiguously assigned, including 159 integral membrane proteins, 35 outer membrane proteins and 114 proteins previously annotated as hypothetical. The former had an average grand average hydrophobicity score of 0.362 and were predicted to separate within a pH range of 4.1-10.6 with molecular mass 8-148 kDa, which represents the largest validated set of integral membrane proteins in this organism to date. A functional classification revealed that a large proportion of the identified proteins were involved in cell envelope biogenesis and energy production and conversion. For the first time, this work provides a global view of the S. flexneri 2a membrane subproteome.