中文摘要：

以蔓陀罗S-腺苷蛋氨酸脱羧酶全长eDNA序列为信息探针，筛选NCBI番茄EST数据库，依据同源EST信息，经人工拼接、RT—PCR及RACE技术验证，获得了1个新的SAMDC基因家族成员，命名为SISAMDC1（GenBank登录号：EF550528），并利用染色体步移技术克隆了879bp的上游调控区域。SISAMDC1 eDNA序列全长1847bp，5′-UTR和3′-UTR分别长523和241bp；存在3个ORF（微型uORF、小型uORF和主ORF），主ORF编码360个氨基酸的SAMDC酶原；SISAMDC1基因组序列全长3648bp，有3个内含子，均位于5′-UTR，所有内含子的剪切位点均符合真核生物“GT-AG”规则。SISAMDCl基因与其它植物来源SAMDC基因同源性较高，与人、大肠杆菌以及酵母的同源性较低。表达谱分析发现，SISAM-DCl基因在番茄根、茎、叶、花蕾、果实等器官中均表达，果实中的表达量相对较高。生物信息学分析表明，SISMDC1基因的上游调控序列存在多个顺式作用元件，如W—box、TATA—box、CAAT—box等。

英文摘要：

The SAMDC cDNA sequence from jimsonwead （GenBank accession No. ： Y07768） was used as electronic probe to hybridize tomato ESTs in GenBank through Blastn search. Based on the contig assembled from homologous ESTs, the full-length cDNA of a new member of SAMDC family in tomato was cloned u- sing RT-PCR and RACE, which is 1 847 bp in length with a 523 bp 5＇-UTR and a 241 bp 3＇-UTR. Corre- sponding DNA sequence is 3 648 bp, containing three introns in 5＇-UTR, and all the cleave sites obey with the GT-AG rule. The gene was designated as SISAMDC1 （GenBank accession No. EF550528）. SISAMDC1 consists of three ORFs （tiny uORF, small uORF and main ORF）, and the main ORF encodes 360 amino acids with a calculated molecular weight of 39 kD. The comparison of deduced amino acid sequence revealed that SISAMDC1 is highly homologous to other plant SAMDCs, but less similar to human and yeast＇s. RT-PCR analysis showed that expression level of SISAMDC1 was higher in fruit than in any other organs. The upstream regulatory sequence was cloned by genome walking. Further analysis showed that the upstream regulatory sequence contains several C/s-acting elements （e. g. W-box, TATA-box, CAAT-box）.