Chloroplast development is characterized by the synthesis and assembly of the photosynthetic complexes of the thylakoid membranes. This maturation process requires the coordinated expression of many nuclearand chloroplastencoded genes. As chloroplasts are semiautonomous organelles, they possess their own genome with its inherent transcriptional and translational machinery. However, nuclear-enco...

Chloroplast RNA metabolism is controlled and excecuted by hundreds of nuclear-encoded, chloroplast-localized RNA binding proteins. Contrary to the nucleo-cytosolic compartment or bacteria, there is little evidence for non-coding RNAs that play a role as riboregulators of chloroplasts. We mined deep-sequencing datasets to identify short (16-28 nt) RNAs in the chloroplast genome and found 50 abun...

Chloroplast mRNA populations are characterized by overlapping transcripts derived by processing from polycistronic precursors. The mechanisms and functional significance of these processing events are poorly understood. We describe a pentatricopeptide repeat (PPR) protein, PPR10, whose binding defines mRNA segments derived from two transcription units in maize chloroplasts. PPR10 interacts in v...

Euglena gracilis chloroplasts contain a 145,000-base pair chromosome that encodes genes for ribosomal, transfer, and messenger RNAs. These genes are transcribed within the organelle by chloroplast RNA polymerase activities that are specific for different classes of RNA. Two transcriptional activities have been isolated from Euglena chloroplasts. (Greenberg, B. M., Narita, J. O., DeLuca-Flaherty...

The Chloroplast Genome Database (ChloroplastDB) is an interactive, web-based database for fully sequenced plastid genomes, containing genomic, protein, DNA and RNA sequences, gene locations, RNA-editing sites, putative protein families and alignments (http://chloroplast.cbio.psu.edu/). With recent technical advances, the rate of generating new organelle genomes has increased dramatically. Howev...

The large subunit of ribulose 1,5-bisphosphate carboxylase (rbcL) and the beta subunit of chloroplast ATP synthase (atpB) are encoded by divergently transcribed genes on the plastid genome. We have identified DNA binding factors specific for sequences located in the intergenic region between these two genes. Soluble plastid extracts from pea or whole cell extracts from maize protected a maize c...

BACKGROUND Antarctic hairgrass (Deschampsia antarctica Desv.) is the only natural grass species in the maritime Antarctic. It has been researched as an important ecological marker and as an extremophile plant for studies on stress tolerance. Despite its importance, little genomic information is available for D. antarctica. Here, we report the complete chloroplast genome, transcriptome profiles ...

Viroids are infectious agents identified only in plants so far. In contrast to viruses, the genome of viroids is composed of a tiny circular RNA (250-400 nt) not coding for proteins, but containing in its compact structure all the information needed for parasitizing the transcriptional and RNA trafficking machineries of their hosts. Viroid infections are frequently accompanied by cellular and d...

Cotranslational protein targeting by the signal recognition particle (SRP) requires the SRP RNA, which accelerates the interaction between the SRP and SRP receptor 200-fold. This otherwise universally conserved SRP RNA is missing in the chloroplast SRP (cpSRP) pathway. Instead, the cpSRP and cpSRP receptor (cpFtsY) by themselves can interact 200-fold faster than their bacterial homologues. Here...

RNA editing in land plant organelles is a process primarily involving the conversion of cytidine to uridine in pre-mRNAs. The process is required for gene expression in plant organelles, because this conversion alters the encoded amino acid residues and improves the sequence identity to homologous proteins. A recent study uncovered that proteins encoded in the nuclear genome are essential for e...