phyA dominates in transduction of red-light signals to rapidly responding genes at the initiation of Arabidopsis seedling de-etiolation
phyA dominates in transduction of red-light signals to rapidly responding genes at the initiation of Arabidopsis seedling de-etiolation
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DOI：
10.1111/j.1365-313x.2006.02914.x
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发表时间：
2006-12-01
期刊：
影响因子：
7.2
通讯作者：
Quail, Peter H.
中科院分区：
文献类型：
--
作者：
Tepperman, James M.;Hwang, Yong-Sic;Quail, Peter H.
与基于连续红光(RC)对幼苗脱黄化的可见表型行为的预期相反，先前的基因表达谱显示，拟南芥的五元光敏色素(PHY)家族中除PhyB以外的一个或多个家族主要负责将RC信号转导到光响应基因。为了开始确定哪些PHY参与了光信号，并确定了PHY信号的潜在主要靶点，我们研究了黑暗生长的野生型、PHYA、PHYB和PHYA双突变体幼苗在最初暴露于光信号后1h内对RC反应的基因的全基因组表达谱。数据表明，PhyA在RC诱导的这些早期反应基因的表达中起着数量上的主导作用，PhyB在PhyA存在的情况下具有最小的可检测到的调节活性，但在不存在时具有更大的数量作用，并且PhyA和PhyB共同负责这些基因中96%的RC响应。没有证据表明其余的家庭成员，PhyC，PHYD或PhyE，在这一过程中发挥了重要作用。与之形成鲜明对比的是，RC对早期反应基因表达的抑制在PhyAphy B双突变体和单基因突变体中仍然在数量上很强，这表明其他三个phy中的一个或多个在这一反应中发挥了重要作用。对已确定或预测的早期反应基因的功能作用的检查表明，编码转录因子的基因是最大的单一类别，其频率是其在整个基因组中流行频率的三倍。这种显性在那些对RC信号反应最强烈的基因中尤其明显，其中>；50%被归类为参与转录调控，这表明这些基因可能在PHY信号和光响应转录网络之间的界面上具有潜在的主要调控作用。将目前的数据与之前对一个pif3突变体进行的基因组规模转录分析的结果相结合，表明了一个复杂的网络，涉及PhyA和PhyB通过PIF3和其他未定义的信号伙伴感知和转导诱导RC信号到早期反应基因。
Contrary to expectations based on the visible phenotypic behavior of seedlings undergoing de-etiolation in response to continuous red light (Rc), previous gene expression profiling showed that one or more of the five-membered phytochrome (phy) family of Arabidopsis, other than phyB, is predominantly responsible for transducing the Rc signals to light-responsive genes. To begin to identify which phys are involved, and to define potential primary targets of phy signaling, we have examined the genome-wide expression profiles of genes responding to Rc within 1 h (early response genes) of initial exposure of dark-grown wild-type, phyA, phyB and phyAphyB double mutant seedlings to the light signal. The data show that phyA has a quantitatively dominant role in Rc-induced expression of these early response genes, that phyB has minimal detectable regulatory activity in the presence of phyA, but assumes a quantitatively larger role in its absence, and that phyA and phyB combined are responsible for the full extent of Rc responsiveness of 96% of these genes. No evidence was obtained of a significant role for the remaining family members, phyC, phyD or phyE, in this process. In striking contrast, Rc-imposed repression of early response gene expression remains quantitatively strong in the phyAphyB double mutant, as well as the monogenic mutants, suggesting a significant role for one or more of the other three phys in this response. Examination of the established or predicted functional roles of the early response genes indicates that genes encoding transcription factors represent the largest single category, at a frequency three times their prevalence genome-wide. This dominance is particularly striking among those genes responding most robustly to the Rc signal, where > 50% are classified as involved in transcriptional regulation, suggesting that these may have potentially primary regulatory roles at the interface between phy signaling and the light-responsive transcriptional network. Integration of the present data with those of a previous genome-scale transcriptional analysis of a pif3 mutant, suggests a complex network involving perception and transduction of inductive Rc signals by both phyA and phyB through both PIF3 and other undefined signaling partners to early response genes.