Development and Molecular Genetics of Embryogenesis in Arabidopsis

Meinke博士的研究目的是识别在植物胚胎发育过程中具有必要功能的基因。方法是分离和鉴定拟南芥的胚胎致死突变体。他在这里建议1)继续对具有有趣的异常发育模式的胚胎致死进行分析；2)尝试识别具有重要发育功能而不是管家功能的基因；3)开发突变基因的分子分离策略。为了便于识别具有重要发育功能的基因，已经提出了几种不同的模型。他计划通过分离更多的突变体来测试这些模型，这些突变体具有不寻常的发育模式，只在胚胎发生期间表达的基因缺陷，与形态发生的关键阶段相对应的致死阶段，以及绿色而不是白色的停滞胚胎。与其他实验室合作，将采用三种不同的方法对胚胎死亡进行分子分析：1)种子转化后用T-DNA标记基因；2)用玉米转座子标记基因；3)通过转化实现染色体行走和分子互补。他建议将他的注意力集中在三个具有特别有趣的表型的突变体上：生物素营养缺陷体(Bio1)；一个融合的子叶/无根突变体(Emb30)；以及一个没有顶端分生组织的绿色圆球突变体(Emb22)。更多的突变体将被定位，为通过染色体行走进行基因分离做准备。发育突变体已被用于各种动物系统，以确定具有重要发育功能的基因。这项提议将这一方法扩展到遗传上可接近的植物拟南芥。

The purpose of Dr. Meinke's research is to identify genes with essential functions during plant embryo development. The approach is to isolate and characterize embryo-lethal mutants of Arabidopsis thaliana. He here proposes to 1) continue the analysis of embryonic lethals with interesting patterns of abnormal development; 2) attempt to identify genes with important developmental rather than housekeeping functions; and 3) develop strategies for the molecular isolation of mutant genes. Several different models have been proposed to facilitate the identification of genes with important developmental functions. He plans to test these models by isolating additional mutants with unusual patterns of development, defects in genes expressed only during embryogenesis, lethal phases that correspond to a critical stage in morphogenesis, and arrested embryos that are green rather than white. Three different approaches to molecular analysis of embryonic lethals will be pursued in collaboration with other laboratories; 1) gene tagging with T-DNA following seed transformation; 2) gene tagging with maize transposable elements; and 3) chromosome walking and molecular complementation through transformation. He proposes to focus his attention on three mutants with particularly interesting phenotypes; the biotin auxotroph (bio1); a fused cotyledon/rootless mutant (emb30); and a green blimp mutant with no apical meristems (emb22). Additional mutants will be mapped in preparation for gene isolation through chromosome walking. %%% Developmental mutants have been used in a variety of animal systems to identify genes with important developmental functions. This proposal extends that approach to the genetically approachable plant, Arabidopsis.