Expression, purification, and structural analysis of HISUBE2G2 (human ubiquitin-conjugating enzyme)

The Protective Effect of UBE2G2 Knockdown Against Atherosclerosis in Apolipoprotein E-Deficient Mice and Its Association with miR-204-5p

Atherosclerosis (AS) is a chronic and progressive inflammatory disease. Ubiquitin-conjugating enzyme E2G 2 (UBE2G2) has been reported to be differentially expressed in subjects with abnormal coronary endothelial function. We intended to further explore the effect of UBE2G2 in AS using apolipoprotein E-deficient (ApoE^-/-) mice. Relative UBE2G2 expression in aortic sinus tissues was examined by Real-time reverse transcriptase-polymerase chain reaction and immunohistochemical staining. Atherosclerotic plaque formation was observed through hematoxylin-eosin staining. The protein levels of adhesion biomarkers and inflammatory cytokines was analyzed by western blotting. The direct interaction between UBE2G2 and miR-204-5p was predicted by bioinformatic analysis, and the correlation was analyzed by Pearson's correlation test, and verified by luciferase reporter assay. Human vascular smooth muscle cells (VSMCs) development was detected by 5-ethynyl-2'-deoxyuridine labeling assay and wound healing assays. UBE2G2 was highly expressed in the aortic sinus tissues of high-fat diet-fed ApoE^-/- mice. The atherosclerotic plaque formation was increased in ApoE^-/- mice, while UBE2G2 knockdown reduced it. Silencing of UBE2G2 also inhibited the expression and protein levels of adhesion biomarkers and inflammatory cytokines in ApoE^-/- mice. MiR-204-5p was the upstream effector of UBE2G2 and miR-204-5p overexpression was found to inhibit the proliferation and migration of human VSMCs through regulating UBE2G2 expression. UBE2G2 inhibition attenuated AS in ApoE^-/- mice and UBE2G2 expression was negatively regulated by miR-204-5p in human VSMCs.

Screening of T7 phage displayed Bactrocera dorsalis (Hendel) antenna cDNA library against chemosensory protein

Recent studies have shown that chemosensory proteins (CSPs) were involved in diverse life activities such as insect feeding, development, mating, immune regulation, as well as other important circadian rhythms, etc. To screen the proteins involved in the BdorCSP-related physiological activity, a cDNA library of the Bactrocera dorsalis (Hendel) antenna expressed on the surface of T7 phage was screened against BdorCSP. After four rounds of screening, ELISA-positive samples of selected phages were sequenced and identified as protein disulfide isomerase (PDI), trypsin-like serine protease (Ser), TakeOut (TO), and a new protein by GenBank blast, respectively. Real-time quantitative PCR results showed that the expression levels of Ser, TO, and the new protein were the highest in antenna, sharing similar expression pattern with BdorCSP. These results reveal that these proteins might be involved in the BdorCSP-related physiological or metabolic activities. This work paves a new way for exploring the function of CSPs.

Rice black streaked dwarf virus P9-1, an alpha-helical protein, self-interacts and forms viroplasms in vivo

Replication and assembly of viruses from the family Reoviridae are thought to take place in discrete cytoplasmic inclusion bodies, commonly called viral factories or viroplasms. Rice black streaked dwarf virus (RBSDV) P9-1, a non-structural protein, has been confirmed to accumulate in these intracellular viroplasms in infected plants and insects. However, little is known about its exact function. In this study, P9-1 of RBSDV-Baoding was expressed in Escherichia coli as a His-tagged fusion protein and analysed using biochemical and biophysical techniques. Mass spectrometry and circular dichroism spectroscopy studies showed that P9-1 was a thermostable, alpha-helical protein with a molecular mass of 41.804 kDa. A combination of gel-filtration chromatography, chemical cross-linking and a yeast two-hybrid assay was used to demonstrate that P9-1 had the intrinsic ability to self-interact and form homodimers in vitro and in vivo. Furthermore, when transiently expressed in Arabidopsis protoplasts, P9-1 formed large, discrete viroplasm-like structures in the absence of infection or other RBSDV proteins. Taken together, these results suggest that P9-1 is the minimal viral component required for viroplasm formation and that it plays an important role in the early stages of the virus life cycle by forming intracellular viroplasms that serve as the sites of virus replication and assembly.

Protein expression changes in the nucleus accumbens and amygdala of inbred alcohol-preferring rats given either continuous or scheduled access to ethanol

Chronic ethanol (EtOH) drinking produces neuronal alterations within the limbic system. To investigate changes in protein expression levels associated with EtOH drinking, inbred alcohol-preferring (iP) rats were given one of three EtOH access conditions in their home-cages: continuous ethanol (CE: 24h/day, 7days/week access to EtOH), multiple scheduled access (MSA: four 1-h sessions during the dark cycle/day, 5 days/week) to EtOH, or remained EtOH-naïve. Both MSA and CE groups consumed between 6 and 6.5g of EtOH/kg/day after the 3rd week of access. On the first day of EtOH access for the seventh week, access was terminated at the end of the fourth MSA session for MSA rats and the corresponding time point (2300h) for CE rats. Ten h later, the rats were decapitated, brains extracted, the nucleus accumbens (NAcc) and amygdala (AMYG) microdissected, and protein isolated for 2-dimensional gel electrophoretic analyses. In the NAcc, MSA altered expression levels for 12 of the 14 identified proteins, compared with controls, with six of these proteins altered by CE access, as well. In the AMYG, CE access changed expression levels for 22 of the 27 identified proteins, compared with controls, with 8 of these proteins altered by MSA, as well. The proteins could be grouped into functional categories of chaperones, cytoskeleton, intracellular communication, membrane transport, metabolism, energy production, or neurotransmission. Overall, it appears that EtOH drinking and the conditions under which EtOH is consumed, differentially affect protein expression levels between the NAcc and AMYG. This may reflect differences in neuroanatomical and/or functional characteristics associated with EtOH self-administration and possibly withdrawal, between these two brain structures.

Structure of human ubiquitin-conjugating enzyme E2 G2 (UBE2G2/UBC7)

The human ubiquitin-conjugating enzyme E2 G2 (UBE2G2/UBC7) is involved in protein degradation, including a process known as endoplasmic reticulum-associated degradation (ERAD). The crystal structure of human UBE2G2/UBC7 was solved at 2.56 angstroms resolution. The UBE2G2 structure comprises a single domain consisting of an antiparallel beta-sheet with four strands, five alpha-helices and two 3(10)-helices. Structural comparison of human UBE2G2 with yeast Ubc7 indicated that the overall structures are similar except for the long loop region and the C-terminal helix. Superimposition of UBE2G2 on UbcH7 in a c-Cbl-UbcH7-ZAP70 ternary complex suggested that the two loop regions of UBE2G2 interact with the RING domain in a similar way to UbcH7. In addition, the extra loop region of UBE2G2 may interact with the RING domain or its neighbouring region and may be involved in the binding specificity and stability.