Studies on the mechanism and factor requirement of nuclear Pre-mRNA processing in plants

This project describes experiments for the isolation and characterization of many plant proteins which are involved in the regulation of gene expression in plants. Their influence on gene regulation by light, metabolic pathways and cell cycle has been investigated in more detail. In principle, these proteins can be used to specifically change gene expression pattern in plants. Pre-mRNA processing is an vital step in the regulation of gene expression in higher eukaryotes leading to functional mRNAs. In this process, the coding regions of a gene (exons) are spliced together and the intervening sequences (introns) are deleted. Whereas the mechanism of RNA splicing appears identical in animal and plant kingdoms, animal introns cannot be correctly recognized in the plant cell. Thus, one aim of this project was to characterize splicing factors from plants involved in intron recognition. Furthermore, these factors are often essential for alternative splicing pathways which frequently regulate the expression of tissue-specific and developmental genes. Thus, the second aim was to investigate the regulation of the expression of these splicing factors. atSRp30 was identified as a splicing protein that changes the splicing pattern of several genes and modulate their gene expression program. atRSp31 is a splicing factor, whose expression is influenced by light and carbohydrates. Overexpression of this protein in transgenic plants makes this plants more stable to these environmental influences. atRSZ33 is a protein which interacts with many splicing factors. Its overexpression in transgenic plants causes a severe phenotype as it influences cell cycle and cell shape.