Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-90187, Umeå, Sweden.
SweTree Technologies AB, P.O. Box 4095, SE-904 03, Umeå, Sweden.
Sci Rep. 2017 Apr 4;7(1):628. doi: 10.1038/s41598-017-00744-1.
The COP9 signalosome (CSN) is an evolutionary conserved multiprotein complex that regulates many aspects of plant development by controlling the activity of CULLIN-RING E3 ubiquitin ligases (CRLs). CRLs ubiquitinate and target for proteasomal degradation a vast number of specific substrate proteins involved in many developmental and physiological processes, including light and hormone signaling and cell division. As a consequence of CSN pleiotropic function, complete loss of CSN activity results in seedling lethality. Therefore, a detailed analysis of CSN physiological functions in adult Arabidopsis plants has been hampered by the early seedling lethality of csn null mutants. Here we report the identification and characterization of a viable allele of the Arabidopsis COP9 signalosome subunit 4 (CSN4). The allele, designated csn4-2035, suppresses the adventitious root (AR) phenotype of the Arabidopsis superroot2-1 mutant, potentially by altering its auxin signaling. Furthermore, we show that although the csn4-2035 mutation affects primary and lateral root (LR) formation in the 2035 suppressor mutant, CSN4 and other subunits of the COP9 complex seem to differentially control AR and LR development.
COP9 信号体（CSN）是一种进化上保守的多蛋白复合物，通过控制 CULLIN-RING E3 泛素连接酶（CRLs）的活性来调节植物发育的许多方面。CRLs 泛素化并靶向蛋白酶体降解大量参与许多发育和生理过程的特异性底物蛋白，包括光和激素信号以及细胞分裂。由于 CSN 的多效性功能，CSN 活性的完全丧失会导致幼苗致死。因此，由于 csn 缺失突变体的早期幼苗致死性，对成年拟南芥植物中 CSN 生理功能的详细分析受到了阻碍。在这里，我们报告了拟南芥 COP9 信号体亚基 4（CSN4）的一个可行等位基因的鉴定和特征。该等位基因，命名为 csn4-2035，可通过改变其生长素信号来抑制拟南芥超级根 2-1 突变体的不定根（AR）表型。此外，我们表明，尽管 csn4-2035 突变会影响 2035 抑制突变体中主根和侧根（LR）的形成，但 CSN4 和 COP9 复合物的其他亚基似乎以不同的方式控制 AR 和 LR 的发育。
