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.