shRNA介导的RNA干扰对小鼠T淋巴细胞CD28基因的沉默效应

目的 探讨短发夹状RNA(shRNA)对C57BL/6J小鼠T淋巴细胞CD28共刺激分子基因沉默效应,评价shRNA对目的 基因干扰效应的时效性和稳定性,筛选出高效的干扰序列用于后期的动物实验.方法 首先构建3个载有CD28特异性shRNA(shRNA1～3)的表达质粒和1个非特异性shRNA表达质粒,将其分别转染小鼠脾淋巴细胞,以非特异性的shRNA表达质粒组和未转染组分别作为阴性对照和空白对照,采用实时荧光定量PCR和Western blot方法分别从基因和蛋白质水平评价转染l～20 d内CD28 shRNA对CD28基因的干扰效应,并筛选出干扰效率最高的序列.结果 ①成功构建了CD28 shRNA表达载体;②3种CD28 shRNA均可在mRNA和蛋白质水平有效沉默目的 基因,与实验对照组比较差异有统计学意义(P＜0.01):CD28 mRNA拷贝数持续降低,3种CD28 shRNA转染C57BL/6J小鼠脾细胞20 d,小鼠脾细胞CD28 mRNA拷贝绝对数分别下降了99.62%、99.89%和99.80%;CD28蛋白表达水平分别降低了(84.90±0.65)%、(96.49±0.03)%和(91.76±0.32)%,以CD28 shRNA 2组的抑制效率最高(P＜0.01).结论 ①特异性的CD28 shRNA可长期、稳定地介导CD28基因沉默;②针对CD28基因不同位点的不同shRNA也有干扰效率的差异.

shRNA mediated silencing effect of RNA interference on the CD28 co-stimulation factor in mice T lymphocyte

OBJECTIVE: To explore the silencing effect of short hairpin RNA (shRNA) on the CD28 of mice T lymphocytes by CD28-shRNA expressing plasmid evaluate the interfering effects (chronergy and stability) mediated by shRNA and select out the most efficient CD28 shRNA sequence. METHODS: Three CD28 specific and one non-specific shRNA expressing plasmids were constructed and then transfected separately into mice spleen T lymphocytes. Non-transfected cells and non-specific shRNA were taken as controls. Inhibitory effect of CD28 shRNA was demonstrated by real-time quantitative PCR and Western blots. The sequence of the highest RNA interference (RNAi) effecacy was screened. RESULTS: (1) CD28 shRNA expressing plasmids were successfully constructed; (2) Three CD28 specific shRNAs effectively inhibited the expression of CD28 at the mRNA and protein levels, and there was a statistically significant difference comparing with the controls (P < 0.01): The copies of CD28 in mice spleen cells at the mRNA levels were persistingly decreased by 99.62%, 99.89% and 99.80% respectively after 20 days, and so did at the protein level [(84.90 +/- 0.65)%, (96.49 +/- 0.03)%, (91.76 +/- 0.32)% respectively]. The highest inhibitory rate was in CD28 shRNA-2 group. CONCLUSIONS: (1) Specific shRNA can mediate long-term and stable silencing effects on CD28 gene; (2) shRNAs matching different sites of CD28 gene exert differential inhibitory effects.