Prominent polypeptides with apparent molecular masses of 180, 120, 85, and 38 kDa are found in an extensively purified preparation of maize chloroplast DNA-dependent RNA polymerase that retains the capacity to initiate transcription of the cloned chloroplast gene rbcL correctly and the requirement for a supercoiled DNA template for specific and active transcription. Amino-terminal amino acid se...

C hloroplasts arose 1.2 billion years ago (1) when a freeliving cyanobacterium became an endosymbiont in a eukaryotic host. Since that time, chloroplast genomes have undergone severe reduction, because chloroplast genomes encode between 50 and 200 proteins, whereas cyanobacterial genomes encode several thousand. Accordingly, endosymbiotic theories have always assumed that the cyanobacterial anc...

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...

The occurrence of homologous DNA recombination in chloroplasts is well documented, but little is known about the molecular mechanisms involved or their biological significance. The endosymbiotic origin of plastids and the recent finding of an Arabidopsis nuclear gene, encoding a chloroplast-localized protein homologous to Escherichia coli RecA, suggest that the plastid recombination system is r...

Chloroplast DNA conformation was analyzed by pulse-field gel electrophoresis. We found that spinach leaf chloroplast DNA molecules exist in at least four distinct forms with the apparent molecular weights of monomer, dimer, trimer, and tetramer. Two-dimensional gel analysis of DNA after UV nicking and in the presence of ethidium bromide indicates that they are not isomers that differ in superhe...

We used DNA sequencing and gel blot surveys to assess the integrity of the chloroplast gene infA, which codes for translation initiation factor 1, in >300 diverse angiosperms. Whereas most angiosperms appear to contain an intact chloroplast infA gene, the gene has repeatedly become defunct in approximately 24 separate lineages of angiosperms, including almost all rosid species. In four species ...

An 11.2-kilobase pair (kbp) BamHI restriction nuclease fragment from spinach chloroplast DNA has been found to contain the gene for the large subunit (LS) of ribulose-1,5-bisphosphate carboxylase [RuP(2) carboxylase; 3-phospho-D-glycerate carboxy-lyase (dimerizing), EC 4.1.1.39]. The gene was located by hybridization of cloned chloroplast DNA fragments containing the maize LS gene (Bedbrook, J....

Previous studies have indicated that in all land plants examined to date, the chloroplast gene trnLUAA isinterrupted by a single group I intron ranging from 250 to over 1400 bp. The parasitic Epifagus virginiana haslost, however, the entire gene. We report that the intron is missing from the chloroplast genome of twoarctic species of the legume genus Hedysarum (H. alpinum, H. ...

Variation of chloroplast DNA and nuclear ribosomal DNA (DNA encoding ribosomal RNA) was studied for five species of white oak native to the eastern United States. Although these species differ in many morphological characters and have different (though overlapping) geographical ranges and ecological tolerances, they are interfertile and often grow in mixed stands, and hybrids are occasionally f...

The DNA in isolated chloroplasts was visualized by the fluorescent probe 4'6-diamidino-2-phenylindole (DAPI). When excited with light of 360 nm, the DNA-DAPI complex fluoresces brilliantly at 450 nm. Nuclei also fluoresce but their nucleoli do not. RNase and Pronase treatment of chloroplasts did not affect the fluorescence but both pre- and posttreatment of DAPI-stained chloroplasts with DNase ...