title: Three dynamin-related protein 5B genes are related to plastid division in Physcomitrella patens.
abstract: Dynamin family proteins in eukaryotic cells assemble into rings or spirals on the surface of membranes and pinch the membranes. We found 21 dynamin-related protein (DRP) genes in the Physcomitrella patens genome. Phylogenetic analysis indicated that three of them (PpDRP5B-1, PpDRP5B-2, and PpDRP5B-3) showed robust monophyly with Arabidopsis thaliana DRP5B and Cyanidioschyzon merolae CmDnm2, both of which are related to plastid division. Quantitative RT-PCR analysis showed that the amounts of DRP5B-3 transcripts were 14-fold and 8-fold higher than those of DRP5B-1 and DRP5B-2, respectively. We generated PpDRP5B knockout transformants for each of these genes. Subapical protonemata cells in wild-type plants had an average of 47 chloroplasts. The cells in the PpDRP5B-3 knockout transformant had slightly enlarged chloroplasts, with an average chloroplast number of 28, whereas the PpDRP5B-1 and 5B-2 knockout lines had no effect on chloroplast number in P. patens. To analyze function of each PpDRP5B gene, we generated double- and triple-knockout lines. Whereas there were 32 chloroplasts in a cell of the PpDRP5B-1/5B-2 double-knockout lines, the triple-knockout line had only a few macrochloroplasts. A transient expression assay with the triple-knockout line demonstrated that the PpDRP5B-3 gene could recover the normal chloroplast phenotype.
authors.affiliation: Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Sakaguchi
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Takechi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sato
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamada
authors.forename: Susumu
authors.initials: S
authors.lastname: Takio
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Takano
mesh_terms: D019068:Bryopsida / Q000235:genetics* / Q000378:metabolism* / Q000648:ultrastructure; D002736:Chloroplasts / Q000378:metabolism* / Q000648:ultrastructure; D034281:Dynamins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D017343:Genes, Plant / Q000235:genetics; D005816:Genetic Complementation Test; D018745:Genome, Plant / Q000235:genetics; D049452:Green Fluorescent Proteins; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D010641:Phenotype; D010802:Phylogeny; D018087:Plastids / Q000378:metabolism* / Q000648:ultrastructure; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D014170:Transformation, Genetic
chemical_list: D049452:Green Fluorescent Proteins; D034281:Dynamins