甘藷中Sporamin基因群的選殖及特性研究

Isolation and Characterization of New Sporamin Gene Members from Sweet Potato (Ipomoea batatas Lam.)

本文中報告了四個Sporamin cDNA基因，其中有二個是全長的基因，另二個則不完整；此四個cDNA基因其序列與以往發表的皆不盡相同，但相似度則達90%以上；根據Gene Bank的資料分析，四者皆屬Sporamin A亞群分子；從南方雜合的資料顯示，其含有相當多的子基因，北方轉印資料顯示，此基因在葉子部不表現，在莖部則微量存在，然而在塊根中則大量表現，故此基因被推論為扮演甘藷塊根中貯藏性蛋白質的功能。

Two full-length and two partial cDNAs encoding sporamin A have been isolated from sweet potato tuberous roots. Sequence comparisons show that they are very similar with 94-98% homology at nucleotide level. and 80-88% at protein level. All four cDNAs possess multiple alternate polyadenylation signals in the 3' untranslated region (3'-UTR). Genomic Southern blot analysis indicates the presence of a sporamin multigene family in sweet potato. High levels of sporamin mRNAs were detected in developing tuberous roots. but they disappeared at the sprout-germinating stage. Differential expression of these genes was obvious as their mRNAs were present specifically in developing roots, rarely in stems and not in leaves.