Functional characterisation of a gene family encoding circadian regulated glycine-rich RNA-binding proteins in Arabidopsis thaliana

该项目的总体目标是对时钟控制的RNA结合蛋白AtGRP7（拟南芥富含甘氨酸的RNA结合蛋白）和AtGRP8进行功能表征。AtGRP7是负反馈回路的一部分，通过该负反馈回路，它调节自身转录物以及atgrp8转录物的振荡。我们认为AtGRP7反馈回路参与了将中央生物钟产生的定时信号传输到细胞内的时钟控制过程。为了定义这个反馈回路的功能，我们建议确定AtGRP7的目标转录本。由于预期此类转录物在组成型过表达AtGRP7（AtGRP7-ox）的转基因植物中显示改变的表达，因此将使用DNA微阵列比较野生型植物和AtGRP7-ox植物之间的转录物谱。此外，将产生Atgrp7和Atgrp8表达降低的转基因植物，以研究表达降低对植物形态和生理的表型后果。为了获得关于AtGRP7和AtGRP8可能优先活跃的条件的全面概述，将考虑潜在的时钟调节来详细研究它们在发育期间以及响应于外部刺激和应激因素的表达模式。

The overall goal of this project is a functional characterisation of the clock-controlled RNA-binding proteins AtGRP7 (Arabidopsis thaliana glycine-rich RNA-binding protein) and AtGRP8. AtGRP7 is part of a negative feedback loop through which it regulates oscillations of its own transcript as well as of the atgrp8 transcript. We suggest that the AtGRP7 feedback loop is involved in transmitting timing signals generated by a central circadian clock to clock-controlled processes within the cell. To define the function of this feedback loop we propose to identify target transcripts of AtGRP7. Since such transcripts are expected to show an altered expression in transgenic plants constitutively overexpressing AtGRP7 (AtGRP7-ox), transcript profiles will be compared between wild type plants and AtGRP7-ox plants employing DNA microarrays. Moreover, transgenic plants with reduced expression of Atgrp7 and Atgrp8 will be generated to investigate the phenotypical consequences of reduced expression for morphology and physiology of the plants. To obtain a comprehensive overview about the conditions under which AtGRP7 and AtGRP8 may preferentially be active, their expression pattern during development and in response to external stimuli and stress factors will be investigated in detail in consideration of the underlying clock regulation.