Zhang S, Williams-Carrier R, Jackson D, Lemaux P G
Department of Plant and Microbial Biology, University of California, Berkeley 94720, USA.
Planta. 1998 Apr;204(4):542-9. doi: 10.1007/s004250050289.
Expression of CDC2Zm and KNOTTED1 (KN1) in maize (Zea mays L.) and their cross-reacting proteins in barley (Hordeum vulgare L.) was studied using immunolocalization during in-vitro axillary shoot meristem proliferation and adventitious shoot meristem formation. Expression of CDC2Zm, a protein involved in cell division, roughly correlated with in-vitro cell proliferation and in the meristematic domes CDC2Zm expression was triggered during in-vitro proliferation. Analysis of the expression of KN1, a protein necessary for maintenance of the shoot meristem, showed that KN1 or KN1-homologue(s) expression was retained in meristematic cells during in-vitro proliferation of axillary shoot meristems. Multiple adventitious shoot meristems appeared to form directly from the KN1- or KN1 homologue(s)-expressing meristematic cells in the invitro proliferating meristematic domes. However, unlike Arabidopsis (Arabidopsis thaliana) and tobacco (Nicotiana tabacum) leaves ectopically expressing KN1 (G. Chuck et al., 1996 Plant Cell 8: 1277-1289; N. Sinha et al., 1993 Genes Dev. 7: 787-797), transgenic maize leaves over-expressing KN1 were unable to initiate adventitious shoot meristems on their surfaces either in planta or in vitro. Therefore, expression of KN1 is not the sole triggering factor responsible for inducing adventitious shoot meristem formation from in-vitro proliferating axillary shoot meristems in maize. Our results show that genes critical to cell division and plant development have utility in defining in-vitro plant morphogenesis at the molecular level and, in combination with transformation technologies, will be powerful tools in identifying the fundamental molecular and-or genetic triggering factor(s) responsible for reprogramming of plant cells during plant morphogenesis in-vitro.
利用免疫定位技术，研究了细胞分裂周期蛋白2玉米（CDC2Zm）和玉米结瘤蛋白1（KN1）在玉米（Zea mays L.）中的表达及其在大麦（Hordeum vulgare L.）中的交叉反应蛋白，该研究是在体外腋芽分生组织增殖和不定芽分生组织形成过程中进行的。CDC2Zm是一种参与细胞分裂的蛋白质，其表达大致与体外细胞增殖相关，并且在体外增殖过程中，分生组织穹顶中的CDC2Zm表达被触发。对维持茎尖分生组织所必需的蛋白质KN1的表达分析表明，在腋芽分生组织的体外增殖过程中，KN1或其同源物的表达保留在分生细胞中。多个不定芽分生组织似乎直接从体外增殖的分生组织穹顶中表达KN1或其同源物的分生细胞形成。然而，与异位表达KN1的拟南芥（Arabidopsis thaliana）和烟草（Nicotiana tabacum）叶片不同（G. Chuck等人，1996年，《植物细胞》8：1277 - 1289；N. Sinha等人，1993年，《基因与发育》7：787 - 797），过表达KN1的转基因玉米叶片在体内或体外均无法在其表面启动不定芽分生组织。因此，KN1的表达不是诱导玉米体外增殖腋芽分生组织形成不定芽分生组织的唯一触发因素。我们的结果表明，对细胞分裂和植物发育至关重要的基因在分子水平上定义体外植物形态发生方面具有实用性，并且与转化技术相结合，将成为识别负责体外植物形态发生过程中植物细胞重编程的基本分子和/或遗传触发因素的有力工具。
