摘要
栽培金鱼草 (AntirrhinummajusL .)中有许多分子生物学上研究得较为透彻的DNA转座子 ,但是它们的S位点已经失去了功能 (Sc)位点 ,故而为自交亲和。为了利用这些转座子进行S位点选择性的转座子标定实验 ,将一个来自栽培金鱼草花型基因Cyc的活跃转座子Tam5通过遗传重组的方法引入到与自交不亲和金鱼草种间杂种(A .majus×hispanicum)S位点紧密连锁的位置。限制性酶切片段长度多态性 (RFLP)的分析证明该转座子距S位点约 3cM (centiMorgan) ,并且保持了较高的转位活性 ,其配子切除频率高达 2 0 %。同时 ,还讨论了花型和自交不亲和性基因连锁的可能的生物学意义。所建立的S位点选择性的转座子标定体系为详细研究金鱼草S核酸酶基因及其不同结构域在自交不亲和反应中的作用提供了新的技术平台。
In order to perform mutational studies on genes from the self_incompatibility ( S ) locus, an S locus_ directed transposon tagging system was established in Antirrhinum . Cultivated lines of Antirrhinum majus contain many molecularly well_characterized transposons, but are self compatible due to the presence of a nonfunctional S locus ( Sc ). In this study, an active transposon ( Tam 5) from the Cycloidea (Cyc ) locus controlling flower asymmetry in A. majus was introduced to a position tightly linked to the functional S locus from self incompatible interspecific hybrids ( A. majus×hispanicum ) through genetic recombination. RFLP (restriction fragment length polymorphism) analysis showed that the transposon is 3 cM (centiMorgan) away from the S locus and retains high transpositional activity with a germinal excision frequency of 20%. Possible implications of the linkage between the S locus and genes controlling floral phenotypes were discussed. An active transposon tightly linked to the S locus constructed here will facilitate the generation of insertional mutants of the S locus encoded genes and may lead to dissecting their precise roles during self_incompatible reactions.
基金
中国科学院"九五"重大项目!(KY95 1_A1_3 0 2 )
国家自然科学基金资助项目!( 3 963 0 0 40
3 982 5 10 3 )
国家攀登计划资助&&
