State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; The University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan District, Beijing 100049, China.
State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
J Genet Genomics. 2014 Dec 20;41(12):617-25. doi: 10.1016/j.jgg.2014.08.009. Epub 2014 Nov 7.
Germlines in plants are formed de novo during post-embryonic development, while little is known about the mechanism that controls this process. In Arabidopsis, the earliest gene controlling this process is SPOROCYTELESS (SPL). A decade ago, we showed that loss of SPL function abolished sporogenesis in both male and female organs of Arabidopsis. However, its function is unclear up to now. In this study, we showed that SPL belongs to a novel transcription repressor family specific in embryophyte, which consists of 173 members in the land plants so far. All of them contain a conserved SPL-motif in their N-terminal and an ethylene-responsive element binding factor-associated amphiphilic repression (EAR) motif in the C-terminal, therefore designated as SPL-like, EAR-containing proteins (SPEARs). Consistently, SPL acts as a transcriptional repressor in yeast and tobacco cells, and SPEAR proteins are able to form homodimer and/or heterodimer with each other in vitro. Furthermore, SPEARs interact with the TOPLESS (TPL) co-repressors via the EAR motif and TCP family transcription factors in yeast cells. Together, we propose that SPL and SPEARs most likely belong to a novel transcription repressor family in land plants which may play a variety of developmental roles in plants.
植物的生殖细胞是在胚胎后发育过程中从头形成的，而控制这一过程的机制知之甚少。在拟南芥中，最早控制这一过程的基因是孢子体（SPL）。十年前，我们发现 SPL 功能丧失会导致拟南芥雄性和雌性器官的孢子发生完全缺失。然而，其功能至今仍不清楚。在这项研究中，我们发现 SPL 属于一个在胚胎植物中特有的新型转录抑制因子家族，到目前为止，在陆地植物中已经有 173 个成员。它们都在 N 端含有一个保守的 SPL 基序，在 C 端含有一个乙烯反应元件结合因子相关的两亲性抑制（EAR）基序，因此被命名为 SPL 样，EAR 含有蛋白（SPEARs）。一致地，SPL 在酵母和烟草细胞中作为转录抑制剂发挥作用，并且 SPEAR 蛋白在体外能够彼此形成同源二聚体和/或异源二聚体。此外，SPEARs 通过 EAR 基序与 TOPLESS（TPL）共抑制因子以及酵母细胞中的 TCP 家族转录因子相互作用。综上所述，我们提出 SPL 和 SPEARs 很可能属于陆地植物中的一个新型转录抑制因子家族，它们可能在植物的各种发育过程中发挥作用。
