Doutriaux M P, Couteau F, Bergounioux C, White C
Institut de Biotechnologie des Plantes, Université Paris-Sud, Orsay, France.
Mol Gen Genet. 1998 Feb;257(3):283-91. doi: 10.1007/s004380050649.
By using RT-PCR and degenerate oligonucleotides based on the sequence homology between the yeast RAD51 and DMC1 genes, two genes belonging to the RAD51 and DMC1 families were isolated from Arabidopsis thaliana ecotype Columbia. A RAD51 genomic DNA was also sequenced which is almost identical to its Landsberg erecta counterpart, except for a few translationally silent substitutions and for the presence of a 527-bp element downstream of the polyadenylation site. This element is repeated in the genome of Arabidopsis. Northern analyses were conducted to characterize the expression pattern of both these genes. AtRAD51 and AtDMC1 are expressed in flower buds, but also in the mitotically active cells from a suspension culture. AtRAD51, but not AtDMC1, transcript level increases after gamma irradiation of the cells. Finally, a synchronisation experiment conducted with the suspension culture indicated that not only AtRAD51 but also AtDMC1 are regulated during the cell cycle, with S-phase-specific induction. Since DMC1 genes have always been regarded as being specifically meiotic, we discuss the significance of this mitotic transcriptional regulation in Arabidopsis.
通过使用基于酵母RAD51和DMC1基因序列同源性的RT-PCR和简并寡核苷酸，从拟南芥生态型哥伦比亚中分离出了属于RAD51和DMC1家族的两个基因。还对一个RAD51基因组DNA进行了测序，它与其兰茨贝格直立型对应物几乎相同，只是有一些翻译沉默取代，并且在多聚腺苷酸化位点下游存在一个527 bp的元件。该元件在拟南芥基因组中重复出现。进行了Northern分析以表征这两个基因的表达模式。AtRAD51和AtDMC1在花芽中表达，但也在悬浮培养的有丝分裂活跃细胞中表达。细胞经γ射线照射后，AtRAD51的转录水平增加，而AtDMC1的转录水平未增加。最后，用悬浮培养进行的同步实验表明，不仅AtRAD51而且AtDMC1在细胞周期中都受到调控，具有S期特异性诱导。由于DMC1基因一直被认为是特异性减数分裂相关的，我们讨论了这种有丝分裂转录调控在拟南芥中的意义。
