Dooner H K, Martínez-Férez I M
The Waksman Institute, Rutgers University, Piscataway, New Jersey 08855, USA.
Genetics. 1997 Dec;147(4):1923-32. doi: 10.1093/genetics/147.4.1923.
Double-strand breaks have been implicated both in the initiation of meiotic recombination in yeast and as intermediates in the transposition process of nonreplicative transposons. Some transposons of this class, notably P of Drosophila and Tc1 of Caenorhabditis elegans, promote a form of homology-dependent premeiotic gene conversion upon excision. In this work, we have looked for evidence of an interaction between Ac transposition and meiotic recombination at the bz locus in maize. We find that the frequency of meiotic recombination between homologues is not enhanced by the presence of Ac in one of the bz heteroalleles and, conversely, that the presence of a homologous sequence in either trans (homologous chromosome) or cis (tandem duplication) does not promote conversion of the Ac insertion site. However, a tandem duplication of the bz locus may be destabilized by the insertion of Ac. We discuss possible reasons for the lack of interaction between Ac excision and homologous meiotic recombination in maize.
双链断裂在酵母减数分裂重组的起始过程中以及非复制型转座子转座过程的中间体中均有涉及。这类转座子中的一些，尤其是果蝇的P元件和秀丽隐杆线虫的Tc1元件，在切除时会促进一种同源依赖性减数分裂前基因转换的形式。在这项研究中，我们寻找了玉米bz位点上Ac转座与减数分裂重组之间相互作用的证据。我们发现，在一个bz杂合等位基因中存在Ac并不会提高同源染色体间减数分裂重组的频率，相反，无论是反式（同源染色体）还是顺式（串联重复）中存在同源序列，都不会促进Ac插入位点的转换。然而，bz位点的串联重复可能会因Ac的插入而变得不稳定。我们讨论了玉米中Ac切除与同源减数分裂重组缺乏相互作用的可能原因。
