NW: Analysis of pentatricopeptide repeat proteins in vivo: targets RNAs and functions I

<p>We want to define targets and functions of selected PPR proteins. The focus is on a subset of PPRs, for which null-alleles in Arabidopsis have been shown to lead to an embryo-defective phenotype. These PPRs are likely to have a very basic function for chloroplast- and thus plant-development, at least in Arabidopsis. The work rests on two general approaches:</p>

<p>1. Definition of PPR RNA Targets</p>

<p>Only for very few RNA binding proteins have target RNAs been determined directly and if so, evidence was based on in vitro studies. We are using a novel approach that couples classical immunoprecipitation techniques with microarray analysis (RIP-Chip).</p>

<p>2. Functional Analysis via Reverse Genetics</p>

<p>It is a well-established fact that chloroplast development in grass species like maize is NOT essential for plant development, quite in contrast to dicot species like Arabidopsis. Therefore, PPR mutants for genes that are essential for embryo development in Arabidopsis will be sought in a maize mutant bank made available by Alice Barkan (http://chloroplast.uoregon.edu/). Recovered mutants will be analyzed for defects in plastid RNA metabolism, guided by RIP-Chip results.</p>