微小杆菌NOS基因密码子偏好性分析

Analysis of codon preference of NOS gene of Exiguobacterium profundum

对微小杆菌NOS基因密码子偏好性进行分析,为后续NOS基因的功能验证及遗传转化等研究提供理论依据。研究表明:微小杆菌NOS基因的密码子偏好性较弱,偏好使用G/C结尾的密码子;比较分析不同细菌NOS基因的密码子偏好性参数,发现不同细菌NOS基因密码子偏好性存在一定差异,整体看,放线菌NOS基因密码子偏好性比蓝藻,厚壁菌门强;与其他细菌NOS基因的CDS序列及RSCU值聚类分析表明,微小杆菌NOS基因与放线菌NOS基因表现出相近的密码子使用偏好性;中性绘图、PR2-plot和ENc-plot分析均表明,自然选择是影响NOS基因密码子偏好性形成的主要因素;与7种模式生物的基因组密码子使用频率比较发现,在异源转化受体选择中,大肠杆菌原核表达系统较酵母菌真核表达系统更适合微小杆菌NOS异源表达,常见5种作物均可作为微小杆菌NOS基因的遗传转化受体,其中水稻更理想。本研究初步揭示了微小杆菌NOS基因密码子使用规律,对后续开展基因功能验证有重要的指导作用,同时也可为生物一氧化氮合成酶进化提供一定科学依据。

Analyzing the codon usage bias of the Exiguobacterium profundum NOS gene provides a theoretical basis for subsequent functional verification and genetic transformation studies.Research indicates that the codon usage bias of the E.profundum NOS gene is relatively weak,with a preference for G/C-ending codons.Comparative analysis of codon usage parameters among different bacterial NOS genes reveals variations in codon preferences,showing that actinobacteria NOS genes exhibit stronger codon bias than those of cyanobacteria and bacteria.Cluster analysis of CDS sequences and RSCU values of various bacterial NOS genes indicates that E.profundum NOS gene shares similar codon usage preferences with actinobacteria NOS genes.Neutral plot,PR2-plot,and ENc-plot analyses all suggest that natural selection is the primary factor influencing the codon usage bias of the NOS gene.Comparing the codon usage frequency with the genomes of seven model organisms,it is found that the E.coli prokaryotic expression system is more suitable for heterologous expression of E.profundum NOS than the yeast eukaryotic expression system.Among five common crops,rice is the most ideal host for genetic transformation of the E.profundum NOS gene.This study preliminarily reveals the codon usage pattern of the E.profundum NOS gene,providing important guidance for subsequent gene function validation and offering scientific insights into the molecular evolution of nitric oxide.