采用RT-PCR方法,首次从木薯华南8号(SC8)克隆一个环指蛋白RFP基因家族成员MeRFP8.该基因cDNA包含1059 bp的开放阅读框,编码一个由352个氨基酸残基组成的蛋白质.该蛋白质分子质量为39.23 ku,理论等电点为4.84,C末端含有保守的结构域RING finger domain(Ring-H2 zinc finger),属于C3H2C3型环指蛋白.利用实时荧光定量PCR分析MeRFP8基因在木薯SC8及其同源四倍体叶片的表达水平,结果显示:5℃低温胁迫24 h内,SC8和其四倍体MeRFP8基因先下调表达,后上调表达,呈"V"字型.而且MeRFP8基因在SC8的表达变化水平比其同源四倍体大.推测MeRFP8基因可能参与木薯的低温响应.%To investigate the role of ring finger protein in plant′s response to cold, a full-length cDNA sequence of MeRFP8 was firstly cloned from cassava SC8 by RT-PCR. The results showed that MeRFP8 gene contained a 1065 bp open reading frame ( ORF) , and encoded 352 amino acid residues, with a predicted molecular mass of 39.23 ku and theoretical isoelectric points ( pI) of 4.84. It had a conserved RING finger domain ( Ring-H2 zinc finger) at the C-terminal region, which belonged to C3H2C3 type ring finger protein. Then expression levels of MeRFP8 gene in cassava SC8 and its autotetraploid genotypes were analyzed using real-time RT-PCR. The results showed that the expression of MeRFP8 in SC8 and its autotetraploid was firstly down-regulated and then up-regulated, presenting a"V" pattern during 24 h at 5℃. Moreover, expression level of MeRFP8 gene was higher in SC8 than its autotetraploid. To summarize, MeRFP8 is likely to be involved in the low temperature response of cassava.
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