2个番木瓜多聚半乳糖醛酸酶抑制蛋白基因的克隆与分析

Cloning and Analysis of Two Polygalacturonase Inhibiting Protein Genes from Papaya

采用RT-PCR扩增获得了2个番木瓜果实多聚半乳糖醛酸酶抑制蛋白(PGIP)基因cDNA和DNA全长序列,将其命名为CpPGIP1和CpPGIP2。CpPGIP1基因全长为984 bp,编码325个氨基酸;CpPGIP2基因全长为1 025 bp,编码326个氨基酸。2基因均没有内含子序列,核苷酸序列有66.54%的相似性,氨基酸序列有63.53%的相似性。2基因均含有植物PGIP基因编码蛋白特有的亮氨酸重复保守序列LXXLXXLXXLXLXXNXLXGXIPXX。对PGIP基因在不同成熟度番木瓜果实表达量分析发现,2基因4个时期均有表达,而且基本呈现同一表达趋势,绿色期表达量最高,随着果实成熟表达量逐渐降低。

Two full-length polygalacturonase inhibiting protein （PGIP） cDNA and DNA were cloned by RT-PCR from papaya and the genes were named as CpPGIP1 and CpPGIP2 respectively. The full length CpPGIP1 was 984 bp which encoding a protein with 325 amino acids. The full length CpPGIP2 was 1 025 bp which coding for 326 amino acids. Sequencing analysis showed that the identical amino acid sequence of the two genes was 63.53%, while the identical nucleotide sequence was 66.54%, and no intron sequences were found in the two genes. The amino acid sequences of the two proteins both contained plant PGIP specific conserved leucine repeat sequence LXXLXXLXXLXLXXNXLXGXIPXX The gene expression patterns in papaya fruit at different ripening stages were analyzed by semi-quantitative RT-PCR. The results showed showed similar trend. The expression of CpPGIP was the that the expression patterns of the two genes basically highest in green stage and decreased gradually with papaya fruit maturing.