Knockdown of NSUN2 Inhibits Melanoma Cells Proliferation by Regulating Cyclin Expression / 中国生物化学与分子生物学报

In order to investigate functions of NOP2/Sun RNA methyltransferase 2 (Nsun2) in melanoma cells, shRNA lentiviral vectors were constructed to target Nsun2 in mouse melanoma B16 cells. After treated B16 cells with recombinant virus, the mRNA and protein levels of NSUN2 in the interference group were significantly reduced, and the knock down efficiency reached 80%. EdU staining assay showed significant inhibition of DNA synthesis in Nsun2 knock-down B16 cells. RNA-seq was used to systematically analyze the gene expression of the Nsun2 knock-down and the control cells. A total of 1062 differentially expressed genes (DEGs) were screened, of which 678 were up-regulated and 384 were down-regulated. DEGs were mainly enriched in chromosome, centromere region, and protein binding GO terms. KEGG analysis showed that DEGs were significantly enriched in cell cycle, DNA replication, cell senescence and other pathways. RT-qPCR and RNA-seq data demonstrated that Cdk2, Ccnal, Cdc25b and other genes related to enhance cell division were significantly down-regulated, while Gadd45g and Gadd45a and other genes arresting cell growth were significantly up-regulated. Collectively, this study indicated that NSUN2 affects melanoma cell proliferation by regulating cell cycle and DNA replication, and provided fundamental data for exploring the molecular mechanism of melanoma genesis and development.

Competing Endogenous RNA Networks Underlying Anatomical and Physiological Characteristics of Poplar Wood in Acclimation to Low Nitrogen Availability.

Although poplar plantations are often established on nitrogen (N)-poor soil, the physiological and molecular mechanisms underlying wood properties of poplars in acclimation to low N availability remain largely unknown. To investigate wood properties of poplars in acclimation to low N, Populus � canescens saplings were exposed to either 50 (low N) or 500 (normal N) �M NH4NO3 for 2 months. Low N resulted in decreased xylem width and cell layers of the xylem (the number of cells counted along the ray parenchyma on the stem cross section), narrower lumina of vessels and fibers, greater thickness of double fiber walls (the walls between two adjacent fiber cells), more hemicellulose and lignin deposition, and reduced cellulose accumulation in poplar wood. Consistently, concentrations of gibberellins involved in cell size determination and the abundance of various metabolites including amino acids, carbohydrates and precursors for cell wall biosynthesis were decreased in low N-supplied wood. In line with these anatomical and physiological changes, a number of mRNAs, long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) were significantly differentially expressed. Competing endogenous RNA regulatory networks were identified in the wood of low N-treated poplars. Overall, these results indicate that miRNAs-lncRNAs-mRNAs networks are involved in regulating wood properties and physiological processes of poplars in acclimation to low N availability.