Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: The YlmG protein has a conserved function related to the distribution of nucleoids in chloroplasts and cyanobacteria | Kabeya et al. BMC Plant Biology 2010 10 57 http 1471-2229 10 57 BMC Plant Biology RESEARCH ARTICLE _ Open Access The YlmlG protein has a conserved function related to the distribution of nucleoids in chloroplasts and cyanobacteria Yukihiro Kabeya 1 Hiromitsu Nakanishi1 Kenji Suzuki1 Takanari Ichikawa2 Youichi Kondou2 Minami Matsui2 and Shin-ya Miyagishima 1 Abstract Background Reminiscent of their free-living cyanobacterial ancestor chloroplasts proliferate by division coupled with the partition of nucleoids DNA-protein complexes . Division of the chloroplast envelope membrane is performed by constriction of the ring structures at the division site. During division nucleoids also change their shape and are distributed essentially equally to the daughter chloroplasts. Although several components of the envelope division machinery have been identified and characterized little is known about the molecular components mechanisms underlying the change of the nucleoid structure. Results In order to identify new factors that are involved in the chloroplast division we isolated Arabidopsis thaliana chloroplast division mutants from a pool of random cDNA-overexpressed lines. We found that the overexpression of a previously uncharacterized gene AtYLMG1-1 of cyanobacterial origin results in the formation of an irregular network of chloroplast nucleoids along with a defect in chloroplast division. In contrast knockdown of AtYLMG1-1 resulted in a concentration of the nucleoids into a few large structures but did not affect chloroplast division. Immunofluorescence microscopy showed that AtYLMG1-1 localizes in small puncta on thylakoid membranes to which a subset of nucleoids colocalize. In addition in the cyanobacterium Synechococcuselongates overexpression and deletion of ylmGalso displayed defects in nucleoid structure and cell division. Conclusions These results suggest that the proper distribution of nucleoids requires the YlmG protein and the mechanism
