Mechanisms of Gene Regulation
Zhang, Xiao-Ning , Edmonds, Jason , Mount, Steve .
The Arabidopsis SR protein splicing factor SR45 is required for normal development and environmental response.
Regulated pre-mRNA splicing generates functional protein diversity and is evolutionary conserved. The serine-arginine-rich (SR) proteins constitute a duplicated and conserved family of pre-mRNA splicing factors. Prior work has shown that overexpression of individual SR proteins in Arabidopsis thaliana can affect a variety of phenotypes. Our lab has identified viable loss-of-function mutants for SR45 genes in Arabidopsis thaliana and has initiated further genetic and functional study in vivo. Earlier work on the SR protein SR45 indicates interaction with other SR proteins and the 5' splice site factor U1 70K. SR45 is ubiquitous in plants. Its relationship to SR proteins in animals is unclear. However, SR45 may be orthologous to the animal protein RNPS1. SR45 has two alternatively spliced isoforms but there has been no data on the regulation of SR45 alternative splicing.
Arabidopsis thaliana plants homozygous for an sr45 loss-of-function allele (sr45-1, which carries the SALK_004132 insertion in an exon) were identified. These sr45-1 plants, in which SR45 expression is not detectable, show significant defects in development and environmental response. In wild type plants, the relative abundance of the major spliced form of the SR45 transcript does not show significant changes either spatially or environmentally, but the abundance of the minor isoform varies with environmental changes (temperature and sugar). In sr45-1 mutants, alternatively spliced isoform of another SR protein gene, SRp30, is elevated in seedlings and rosette leaves but not in other tissues. Interestingly, alternatively spliced isoforms of SRp30 are negatively correlated with the minor SR45 isoform, indicating that SRp30 may be a direct target of SR45 regulation.
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1 - University of Maryland, Cell Biology and Molecular Genetics, 3209 HJ Patterson Hall, University of Maryland, College Park, MD, 20742, USA
2 - University of Maryland, Cell Biology and Molecular Genetics
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM