Peters Benjamin, Casey Jonathan, Aidley Jack, Zohrab Stuart, Borg Michael, Twell David, Brownfield Lynette
Department of Biochemistry, University of Otago, Dunedin 9016, New Zealand (B.P., J.C., S.Z., L.B.); and.
Department of Genetics, University of Leicester, Leicester LE1 7RH, United Kingdom (J.A., M.B., D.T.).
Plant Physiol. 2017 Jan;173(1):280-293. doi: 10.1104/pp.16.01192. Epub 2016 Sep 13.
The development of the male germline within pollen relies upon the activation of numerous target genes by the transcription factor DUO POLLEN1 (DUO1). The expression of DUO1 is restricted to the male germline and is first detected shortly after the asymmetric division that segregates the germ cell lineage. Transcriptional regulation is critical in controlling DUO1 expression, since transcriptional and translational fusions show similar expression patterns. Here, we identify key promoter sequences required for the germline-specific regulation of DUO1 transcription. Combining promoter deletion analyses with phylogenetic footprinting in eudicots and in Arabidopsis accessions, we identify a cis-regulatory module, Regulatory region of DUO1 (ROD1), which replicates the expression pattern of DUO1 in Arabidopsis (Arabidopsis thaliana). We show that ROD1 from the legume Medicago truncatula directs male germline-specific expression in Arabidopsis, demonstrating conservation of DUO1 regulation among eudicots. ROD1 contains several short conserved cis-regulatory elements, including three copies of the motif DNGTGGV, required for germline expression and tandem repeats of the motif YAACYGY, which enhance DUO1 transcription in a positive feedback loop. We conclude that a cis-regulatory module conserved in eudicots directs the spatial and temporal expression of the transcription factor DUO1 to specify male germline fate and sperm cell differentiation.
花粉内雄性生殖系的发育依赖于转录因子双花粉1（DUO1）对众多靶基因的激活。DUO1的表达仅限于雄性生殖系，在分离生殖细胞谱系的不对称分裂后不久首次被检测到。转录调控对于控制DUO1的表达至关重要，因为转录和翻译融合显示出相似的表达模式。在这里，我们确定了DUO1转录的生殖系特异性调控所需的关键启动子序列。通过将启动子缺失分析与真双子叶植物和拟南芥种质中的系统发育足迹分析相结合，我们确定了一个顺式调控模块，即DUO1调控区（ROD1），它在拟南芥（Arabidopsis thaliana）中复制了DUO1的表达模式。我们表明，来自豆科植物蒺藜苜蓿的ROD1在拟南芥中指导雄性生殖系特异性表达，证明了真双子叶植物中DUO1调控的保守性。ROD1包含几个短的保守顺式调控元件，包括三个DNGTGGV基序拷贝，这是生殖系表达所必需的，以及YAACYGY基序的串联重复，其在正反馈回路中增强DUO1转录。我们得出结论，真双子叶植物中保守的顺式调控模块指导转录因子DUO1的时空表达，以确定雄性生殖系命运和精子细胞分化。
