The repair of DNA damage and maintenance of genomic stability are essential for the normal growth and adverse defense of plants and animals. In view of the genomic instability caused by the misincorporation of DNA polymerase, this study took DNA polymerase η as the research object and screened its possible small molecule inhibitors by computational simulated molecular docking and detected their enzyme kinetic parameters. The results showed that deoxyadenosine triphosphate (dATP) had an inhibitory effect on the activity of DNA polymerase η, resulting in a relative extension efficiency of 36% to 42%. Simulated molecular docking and in vitro experimental results showed that cyclic GMP-AMP (cGAMP) had a lower binding energy (with an affinity of －35.1 kJ/mol) than dATP (with an affinity of －26.7 kJ/mol) to DNA polymerase η. Enzyme kinetic experiments also showed that cGAMP had a stronger inhibitory ability than dATP and achieved the maximum effect at the concentration of 0.5 mmol/L (with a relative extension efficiency of 13%). Therefore, a potential small molecule inhibitor targeting DNA polymerase η was screened out in this study. At the same time, in view of the tolerance to antitumor drug (DNA damage agent) caused by high expression of this protein, these results provide a basis for the development of new drugs.

To investigate the function and structure of the heat shock protein (HSP) family in Trametes gibbosa,a cDNA library was constructed by collecting mycelial samples at different time under the sawdust treatment.All the HSP genes in this strain were screened by analyzing their transcriptome data; subsequently, bioinformatics analysis was performed for all the HSPs. Gene cloning and sequence structure analysis were performed for the HSP100 family, and the expression levels of the HSP100 genes were verified under the sawdust treatment by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). The results were as follows: A total of 32 HSP genes were screened and divided into five subclasses in T. gibbosa. Among the 32 HSPs, there were two HSP100, two HSP90, seven HSP70, one HSP60 and twenty small HSPs (sHSPs). In growth regulation, they had important functions, such as protein posttranslational modification, protein folding, and chaperonin. In T. gibbosa, HSPs were hydrophobic proteins with distinct physicochemical properties for different subclasses. The HSP100 family consist of an N-terminus, nucleotide-binding domain 1 (NBD1), NBD2, and the linker between the two NBDs. The NBDs had highly conserved Walker A and Walker B motifs and arginine finger residues. The qRT-PCR amplification results showed that there was obvious upregulation expression of HSP100 gene in T. gibbosa under the sawdust treatment. In summary, the classification of the HSP family in T. gibbosa is diverse and complex. Under stress conditions, the HSP100 family plays an important role in protein depolymerization, and its sequence and structure are relatively conserved. The above results can provide a theoretical basis for the study of T. gibbosa under stress.

In order to explore whether heat shock transcription factor (HSF) known to be involved in plant adaptation to extreme heat stress is also involved in plant thermomorphogenesis at warm temperatures, the result of CRISPR/Cas9 gene editing, physiological and biochemical, genetic experiments, and effector-reporter assay demonstrated that the heat shock transcription factor HSFB2b was induced by the warm temperature and played an important role in the process of plant thermomorphogenesis. Under the warm temperature (29 ℃), the Arabidopsis mutant hsfb2b exhibited a longer hypocotyl than the wild type, suggesting that HSFB2b functioned as a negative regulator in thermomorphogenesis. Subcellular localization results showed that the HSFB2b protein was localized in the nucleus. Real-time quantitative polymerase chain reaction (qRT-PCR) analysis showed that the heat shock proteins (HSPs) gene, the heat shock transcription factor HSFA2, and the jasmonic acid degradation gene ST2A were up-regulated in the wild type under the warm temperature relative to the normal temperature (22 ℃), but these genes were more up-regulated by the warm temperature in the hsfb2b mutant than that in the wild type. Furthermore, effector-reporter assay demonstrated that HSFB2b could inhibit ST2A expression by binding to the heat shock element (HSE). In conclusion, the heat shock transcription factor HSFB2b induced by the warm temperature played a negative regulatory role in the hypocotyl elongation and negatively regulated the expression of gene ST2A by recognizing the HSE in molecular mechanism, thusnegatively regulated the plant thermomorphogenesis.

To explore the mechanism of seven factors (Jdp2-Jhdm1b-Mkk6-Glis1-Nanog-Esrrb-Sall4)-induced somatic cell reprogramming, we analyzed the related role of homeobox C8 (Hoxc8) in the process of pluripotency network reconstruction through forward and reverse genetics, quantitative analysis of the classic reprogramming process, and simultaneous knockdown of Hoxc8 and SMAD family member 6 (Smad6). The results showed that knockdown of Hoxc8 could significantly inhibit seven factors-induced somatic cell reprogramming, but overexpression of Hoxc8 had no effects. Furthermore, knockdown of Hoxc8 neither impeded the up-regulation of pluripotency marker genes and down-regulation of somatic cell marker genes nor impeded the expressions of mesenchymal-epithelial transition (MET) marker genes and cell proliferation marker genes. It was also found that simultaneous knockdown of Hoxc8 and Smad6 could rescue the inhibitory effects caused by knocking down Hoxc8 alone. In conclusion, these results suggest that Hoxc8 plays a pivotal role in somatic cell reprogramming, which provides a reference for further revealing the mechanism of Hoxc8 regulating cell fate transition.

In order to evaluate systematically the biological functions of outer membrane proteins (OMPs) under environmental stresses, we selected Aeromonas hydrophila ATCC 7966 as the research object, and constructed 33 OMP deletion strains to determine their growth status under the stress conditions of osmotic pressure, metal ions, H₂O₂ and pH. The results showed that the AHA_0461 and AHA_4275 (encoding TonB protein family) knockout strains grew better than the wild type strain under the osmotic pressure stress. The AHA_2282 (encoding an unknown functional protein) knockout strain grew weakly under the metal ion stresses, while ΔAHA_0904 strain grew better under the osmotic pressure stress. The AHA_2145 (encoding long-chain fatty acid transporter) knockout strain grew weakly under the H₂O₂ and metal ion stresses. The growth of AHA_1279, AHA_1281 (encoding OmpA family protein)and pilQ, AHA_0569 (encoding secretin family protein) knockout strains was weaker than the wild type strain under the H₂O₂ stress. It was suggested that these OMPs may play important roles in response to environmental stresses. These results may highlight a comprehensive understanding of the physiological functions of bacterial OMPs under different environmental stresses in the future, and provide possible targets for the prevention and control of this pathogen.