盾叶薯蓣环阿屯醇合酶全长基因的克隆与分析

环阿屯醇合酶(cycloartenol synthase,CAS)是薯蓣皂甙元生物合成途径中的第一个关键酶.以基因组DNA为模板,利用染色体步行和长距离PCR方法首次克隆了盾叶薯蓣CAS全长基因.序列分析比较结果表明,盾叶薯蓣CAS全长基因为7 192 bp,由18个外显子和17个内含子组成.外显子总长为2 280 bp,编码759个氨基酸,最长的外显子为198 bp,最短的为47 bp;内含子总长4 912 bp,最长的内含子为1 551 bp,最短的为68 bp.Southern blot杂交分析表明,CAS基因在盾叶薯蓣基因组中为单拷贝.

Molecular Cloning and Analysis of the Full-length Cycloartenol Synthase Gene from Dioscorea zingiberensis Wright

Dioscorea zingiberensis Wright is the main material in China for production of diosgenin.Cycloartenol synthase (CAS) is the first committed enzyme for diosgenin biosynthesis.The full-length CAS gene was cloned from D.zingiberensis for the first time by Chromosome Walking and Long-distance PCR methods using the genomic DNA as templates.Sequence analysis showed that the full-length CAS gene of D.zingiberensis was 7 192 bp,consisting of 18 exons and 17 introns.Total length of exons was 2 280 bp,encoding 759 amino acids;The longest exon was 198 bp and the shortest one was 47 bp;Total length of introns was 4 912 bp,the longest intron was 1 551 bp and the shortest one was 68 bp.Southern blot analysis revealed that there was a single copy of CAS gene in D.zingiberensis genome.