Open AccessThe active digestion of uniparental chloroplast DNA in a single zygote of Chlamydomonas reinhardtii is revealed by using the optical tweezer
Author(s) -
Yoshiki Nishimura,
Osami Misumi,
Sachihiro Matsunaga,
Tetsuya Higashiyama,
Akiho Yokota,
Tsuneyoshi Kuroiwa
Publication year - 1999
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.96.22.12577
Subject(s) - chloroplast dna , chlamydomonas reinhardtii , biology , zygote , chlamydomonas , nucleoid , genetics , non mendelian inheritance , gene , organelle , chloroplast , mitochondrial dna , escherichia coli , mutant , embryogenesis
The non-Mendelian inheritance of organelle genes is a phenomenon common to almost all eukaryotes, and in the isogamous algaChlamydomonas reinhardtii , chloroplast (cp) genes are transmitted from the mating type positive (mt + ) parent. In this study, the preferential disappearance of the fluorescent cp nucleoids of the mating type negative (mt − ) parent was observed in living young zygotes. To study the change in cpDNA molecules during the preferential disappearance, the cpDNA ofmt + ormt − origin was labeled separately with bacterialaadA gene sequences. Then, a single zygote with or without cp nucleoids was isolated under direct observation by using optical tweezers and investigated by nested PCR analysis of theaadA sequences. This demonstrated that cpDNA molecules are digested completely during the preferential disappearance ofmt − cp nucleoids within 10 min, whereasmt + cpDNA and mitochondrial DNA are protected from the digestion. These results indicate that the non-Mendelian transmission pattern of organelle genes is determined immediately after zygote formation.