HIGH CHLOROPHYLL FLUORESCENCE145 Binds to and Stabilizes the psaA 5′ UTR via a Newly Defined Repeat Motif in Embryophyta

摘要: The seedling-lethal Arabidopsis thaliana high chlorophyll fluorescence145 (hcf145) mutation leads to reduced stability of the plastid tricistronic psaA-psaB-rps14 mRNA and photosystem I (PSI) deficiency. Here, we genetically mapped HCF145 gene, which encodes a plant-specific, chloroplast-localized, modular protein containing two homologous domains related polyketide cyclase family comprising 37 annotated proteins unknown function. Two further highly conserved previously uncharacterized tandem repeat motifs at C terminus, herein designated transcript binding motif (TMR) domains, confer sequence-specific RNA capability HCF145. Homologous TMR are often found as multiple repeats in quite diverse green red algae cyanobacterium Microcoleus sp PCC 7113 with represents only vascular plants. Detailed analysis hcf145 mutants Physcomitrella patens well vivo vitro assays indicate that has been recruited embryophyta for stabilization via specific its 5′ untranslated region. cyclase-related support association TMRs psaA RNA, presumably pointing regulatory role adjusting PSI levels according requirements plant cell.