A novel DNA methylation motif identified in Bacillus pumilus BA06 and possible roles in the regulation of gene expression.

Single-molecule real-time (SMRT) sequencing can be used to identify a wide variety of chemical modifications of the genome, such as methylation. Here, we applied this approach to identify N6-methyl-adenine (m6A) and N4-methyl-cytosine (m4C) modification in the genome of Bacillus pumilus BA06. A typical methylation recognition motif of the type I restriction-modification system (R-M), 5'-TCm6AN8TTGG-3'/3'-AGTN8m6AACC-5', was identified. We confirmed that this motif was a new type I methylation site using REBASE analysis and that it was recognized by a type I R-M system, Bpu6ORFCP, according to methylation sensitivity assays in vivo and vitro. Furthermore, we found that deletion of the R-M system Bpu6ORFCP induced transcriptional changes in many genes and led to increased gene expression in pathways related to ABC transporters, sulfur metabolism, ribosomes, cysteine and methionine metabolism and starch and sucrose metabolism, suggesting that the R-M system in B. pumilus BA06 has other significant biological functions beyond protecting the B. pumilus BA06 genome from foreign DNA.

Expression of Notch signaling pathway in temporomandibular osteoarthritis / 口腔疾病防治

Objective@# To investigate the expression of Notch signaling molecules in temporomandibular joint arthritis (TMJOA), and to explore the role and mechanism of Notch signaling pathway in the development and progression of TMJOA. @*Methods @#72 Kunming mice were randomly divided into experimental group, sham-surgery group and normal group. In experimental group, discs on the right TMJ were subjected to total discectomy, sham-operation group underwent the same procedure without disc removal, while normal group serve as blank control. All the left temporomandibular joint discs were not treated. 8 mice in each group were sacrificed respectively at 1 week, 2 week, 4 week after surgery. Histological examinations were performed to assess success of TMJOA model, according to the pathological standard of osteoarthritis diagnosis. Immunochemistry techniques were performed in the successful TMJOA cartilages to evaluate the expression levels of Notch1 (NICD1), Jagged1, Hes1 and Hes5. The scores were evaluated by semi-quantitative method. @*Results @#Notch1 (NICD1), Jagged1 and Hes5 were activated in the experimental group with the expression levels increased dramatically over time. While Hes1 expression was suppressed at the beginning of osteoarthritis but was up-regulated afterwards.@*Conclusion @# Notch pathway-related molecular expression changed greatly in TMJOA model, indicating that the pathway in the occurrence and development of TMJOA plays an important role.