荔枝APETALA1（AP1）同源基因cDNA全长克隆及其表达研究

 应用RT-PCR方法克隆得到荔枝AP1同源基因cDNA全长，命名为LcAP1（基因登录号：JN214349）。LcAP1基因开放阅读框738 bp，编码245个氨基酸，推测蛋白质分子量为28.39 kD，等电点为9.69。序列分析显示，LcAP1基因编码的蛋白在1 ~ 61氨基酸含有1个MADS盒结构域，在89 ~ 179氨基酸有1个K盒结构域。蛋白质二级结构预测表明，LcAP1基因编码的蛋白有3个α螺旋，2个β折叠区，8个β转角。同源分析表明，LcAP1基因在不同植物中的一致性为72% ~ 82%。半定量RT-PCR分析表明，在‘三月红’荔枝花芽分化期，LcAP1基因在成熟叶、幼叶、老茎、嫩茎、花芽和花梗中均表达，在花芽中表达最多。

Cloning and Expression Analysis of the APETALA1(AP1)Homologous Gene cDNA from Litchi chinensis

A full-length cDNA sequence of homologous AP1 gene was cloned by employing RT-PCR from Litchi chinensis，which was named as LcAP1（GenBank accession No. JN214349）. The LcAP1 gene open reading frame（ORF）is 738 bp in length，encoding a protein of 245 amino acids，with an estimated molecular weight and an isoelectric point of 28.39 kD and 9.69 respectively. The bioinformatics characterization indicated that the protein encoded by LcAP1 gene has a MADS-box domain（1st–61st），a K-box domain（89th–179th）. Prediction of the secondary structure of the protein showed that LcAP1 protein has 3 α-helices，2 β-strands and 8 β-turns. A comparison of the nucleotide sequences of homologous AP1 genes from different species indicated that LcAP1 gene has a range of 72% to 82% identity in nucleotide sequence with homologues of other plants. Expression analysis by RT-PCR indicted that the LcAP1 gene expressed in mature leaf，young leaf，mature stem，young stem，flower bud and peduncle during‘Sanyuehong’litchi flower bud differentiation period，but expressed more in flower bud.