BRPF1新型转录本BRPF2的鉴定及其在小鼠组织中的表达

BRPF2,a novel transcript of BRPF1 and their expression in mice tissues

为鉴定BRPF1的一种新转录本,确定其在小鼠组织中的表达并对其蛋白功能进行初步研究,将获得的克隆进行序列测定。RT-PCR和Northern blotting实验检测BRPF1和BRPF2在小鼠各组织器官中的表达,生物信息学分析其保守结构域和蛋白功能,并使用TNT T7体外转录翻译系统获得BRPF1和BRPF2蛋白。结果表明BRPF2是BRPF1的一种新型转录本(GenBank登录号:DQ288860);在小鼠肝、胚胎、附睾、睾丸、卵巢和骨骼肌中均检测到BRPF1和BRPF2两个转录本,其中以BRPF1为主要的转录本;而在小鼠脾中,仅检测到BRPF2的转录本;BRPF1编码1246个氨基酸残基,其编码的蛋白质分子量为140 kDa;而BRPF2由于选择性剪接,导致翻译提前终止,仅编码442个氨基酸残基;CDD软件分析BRPF1和BRPF2结构域表明:与BRPF1相比,BRPF2蛋白缺失了Bromodomain结构域和PWWP结构域。鉴于Bromodomain结构域和PWWP结构域是BRPF1蛋白结合乙酰化或非乙酰化组蛋白,募集组蛋白乙酰转移酶Moz和参与染色质重构的关键,暗示BRPF2极有可能是做为BRPF1蛋白的负调控因子,共同参与染色质调控。

In order to identify a novel transcript of BRPF 1 （BRPF2）, a clone separated from mouse cDNA library was sequenced and submitted to GenBank. The expressions of BRPF1 and BRPF2 in different mice tissues were detected using RT-PCR and Northern blotting assays. The preliminary protein functions and conservative domains were analyzed by bioinformatic methods. The results indicated that BRPF2 was a novel transcript ofBRPF1. Both BRPF1 and BRPF2 transcripts could be detected in most mice tissues, including liver, embryo, epididymis, testis, ovary and muscle. However, only BRPF2 transcript could be detected in the spleen. BRPF 1 mRNA encoded 1 246 aa and the predicted molecular mass was 140 kDa, while BRPF2 encoded 442 aa, partly owing to the absence of a new stop codon. The results of CDD analysis suggested that BRPF2 lost the bromodomain and the PWWP domain compared to BRPF1. Because the bromodomain and the PWWP domain are the critical structures of BRPF1 to interact with histones and recruit the other transcriptional factors,BRPF2 （without these two critical domains） may serve as a negative regulatory factor of BRPF1 and be involved in the chromosome remodeling and transcriptional regulating.