Chloroplasts genes

D. E. Soltis. P. S. Soltis, D. R. Morgan, S, M, Swensen, B. C, Mullin, J, M, Dowd, and P. G. Martin, Chloroplast gene sequence data suggest a single origin of predisposition for symbiotic nitrogen fixation in angiosperms. Proc. Natl. Acad. Sci. U.S.A. 92 2646-2651 (1995). 

How did mitochondria and chloroplasts become fixed - fixtures - in nucleated cells The answer would seem to be, at least in part, through this down-sizing . Mitochondrial and chloroplast genes did not disappear, however, so much as they moved to the nucleus of their host cell (reviewed byGillham, 1994). 

S, 5S and 4.5S rRNAs) and a small 30S subunit (containing 16S rRNA). Chloro-plast ribosomal proteins are encoded by both nuclear and chloroplast genes. 

Like mitochondria, chloroplasts contain their own DNA and protein-synthesizing machinery. Some of the polypeptides of chloroplast proteins are encoded by chloroplast genes and synthesized in the chloroplast others are encoded by nuclear genes, synthesized outside the chloroplast, and imported (Chapter 27). When plant cells grow and divide, chloroplasts give rise to new... 

Mitochondrial and chloroplast genes are discussed in Chapters 18 and 23, respectively. 

Y Nagano, R Matsuno, Y Sasaki. An essential gene of Escherichia coli that has sequence similarity to a chloroplast gene of unknown function. Mol Gen Genet 228 62-64, 1991. 

Pfannschmidt T, Nilsson A, Allen JF (1999) Photosynthetic control of chloroplast gene expression. Nature 397 625-628... 

Macheral, D., Kobayashi, FI., Akazawa, T., Kawano, S., and Kuioiwa, T. 1985. Amyloplast nucleoids in sycamore cells and presence of amyloplast DNA of homologous sequences to chloroplast genes. Biochem. Biophys. Res. Commun. 133,140-146. 

Fig. 1.7 Evolution of alkaloids in the phylogeny of plants. Using nucleotide sequences of the chloroplast gene rbcL a phylogenetic tree was computed with Maximum Parsimony. A bootstrap cladogram is shown with bootstrap values shown at the nodes. Branches leading to taxa that accumulate alkaloids are shown in bold.

At present it is debatable whether all chloroplastic MIPS are splice variant of the cytosolic form (Lackey et al., 2003) or they are descendants of the cyanobacterial form. It might even be possible to find more than one chloroplastic MIPS enzyme with different origins. However, until the chloroplastic gene is cloned and the recombinant protein is characterized for its enzymatic properties, the debate remains open with lively and exciting discoveries ahead. 

As with all the other photosynthetic membrane complexes, the genes for the components of the cytochrome complex are distributed between the nuclear and chlo-roplast genomes of higher plants. The chloroplast genes for the Cyt /, Cyt 6-563 and 17 kDa polypeptides have been extensively characterized, but the nuclear gene(s) for the Rieske Fe-S protein have not yet been isolated. 

The chloroplast genes for the CFq subunits IV, III and I and for the a subunit of CFj are co-transcribed to give a primary transcript which is then processed to remove the intron in atp and to generate a number of smaller transcripts [148]. Nothing is known of the mechanisms of these processing events. The chloroplast genes for the /3 and e subunits of CFx are also co-transcribed [151,152]. The transcripts are translated on chloroplast ribosomes, as indicated by the sensitivity of... 

The transcriptions of several of the chloroplast genes are induced by light. The best studied example is the 32 kDa polypeptide of photosystem II [21]. It seems as if light induces the removal of a repressor or promotes the initiation of transcription... 

LE Fish, U Kck and L Bogorad (1985) Two partially homologous adjacent light-inducible maize chloroplast genes encoding polypeptides of the P700 chlorophyll a-protein complex of photosystem I. J Biol Chem 260 1413-1421... 

R Schantz and L Bogorad (1988) Maize chloroplast gene ndhD ndhE and psaC sequences transcripts and transcript poets. Plant Mol Biol 11 239-247... 

This second mechanism is due to a point mutation at the chloroplast gene encoding for a Photosystem II 32 KD membrane protein (3). 

Birky, C. W. Jr. Uniparental inheritance of mitochondrial and chloroplast genes mechanisms and evolution. Proceedings of the National Academy of Sciences USA 92 11331-11338 1995. 

Some chloroplast genes are coded in the organelle genome, and some are in the cell nucleus. 

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