编码荔枝乙烯受体(LcERS1)的cDNA基因的克隆与分析

Cloning and Analyzing of a cDNA for Ethylene Receptor,LcERS1, of Lychee (Litchi chinensis)

利用RT -PCR和RACE方法获得了编码荔枝乙烯受体的cDNA序列 ,长度为 2 ,193bp ,该序列中包含一个ORF全长 1,84 8bp ,编码 6 15个氨基酸 ,推测的分子量为 6 8kD。由该序列推定的蛋白质氨基末端存在疏水区 ,羧基端存在组氨酸激酶区和GAF区。与拟南芥的五个乙烯受体比较 ,推定的荔枝乙烯受体的激酶区有乙烯受体所具有的 5个基序 (H ,N ,G1,F ,G2 )中的H和N基序 (motif) ,分别位于第4 2 3- 4 32和 5 32 - 5 4 3氨基酸 ,其保守序列H为 :MNHEMRTPM ;N为 :LMQTILNIMGNA。结构分析和功能预测表明 ,本研究获得的荔枝乙烯受体编码序列推定的氨基酸序列具有乙烯受体的典型特征 ,初步分析表明获得的荔枝cDNA序列包含了编码荔枝乙烯受体 ,LcERS1,的全长cDNA基因 (lcers1) ,GenBank登录号为AY311484。

The cDNA for an ethylene receptor, LcERS1, of Lychee (Litchi chinensis Sonn.) was obtained by a combination of RT-PCR and RACE technique. The length of cloned cDNA was 2,193 bp, which include an Open Reading Frame of 1,848 bp, from No.87 to No.1934, encoding 615 amino acids, and about 68kD molecular weights. Genbank accession number for LcERS1 is AY311484. The putative protein has three conserved regions, one of them has the homologue with the histidine kinase A (phosphoreceptor) region, dimerisation and phosphoacceptor domain of histidine kinases. These regions are typical phosphotransfer site in the signal transduction system. The other region is GAF domain, which has more positives with the ethylene receptor gene (ers). The analysis of the protein structure and function suggested this putative protein be similar to the ethylene receptor gene, histidine protein kinase and the kinase region of the bacterium two-component signaling. The H and F motifs of the ethylene receptor genes were observed in the kinase region of the putative protein of lychee, they lies in the 423-432 amino acid residues and 532-543 the amino acid residues respectively. The conserved sequence of H is MNHEMRTPM,and F is LMQTILNIMGNA. The putative protein we obtained from lychee has the typical characters of ethylene receptor gene, which including three transmembrane regions in the N-terminal, one conserved histidine kinase domain and one GAF domain in the C-terminal. We strongly suggested that the cDNA sequence from lychee be the full length cDNA gene of the ethylene receptor gene (ers) .