title: Cyanidioschyzon merolae genome. A tool for facilitating comparable studies on organelle biogenesis in photosynthetic eukaryotes.
abstract: The ultrasmall unicellular red alga Cyanidioschyzon merolae lives in the extreme environment of acidic hot springs and is thought to retain primitive features of cellular and genome organization. We determined the 16.5-Mb nuclear genome sequence of C. merolae 10D as the first complete algal genome. BLASTs and annotation results showed that C. merolae has a mixed gene repertoire of plants and animals, also implying a relationship with prokaryotes, although its photosynthetic components were comparable to other phototrophs. The unicellular green alga Chlamydomonas reinhardtii has been used as a model system for molecular biology research on, for example, photosynthesis, motility, and sexual reproduction. Though both algae are unicellular, the genome size, number of organelles, and surface structures are remarkably different. Here, we report the characteristics of double membrane- and single membrane-bound organelles and their related genes in C. merolae and conduct comparative analyses of predicted protein sequences encoded by the genomes of C. merolae and C. reinhardtii. We examine the predicted proteins of both algae by reciprocal BLASTP analysis, KOG assignment, and gene annotation. The results suggest that most core biological functions are carried out by orthologous proteins that occur in comparable numbers. Although the fundamental gene organizations resembled each other, the genes for organization of chromatin, cytoskeletal components, and flagellar movement remarkably increased in C. reinhardtii. Molecular phylogenetic analyses suggested that the tubulin is close to plant tubulin rather than that of animals and fungi. These results reflect the increase in genome size, the acquisition of complicated cellular structures, and kinematic devices in C. reinhardtii.
authors.affiliation: Laboratory of Cell Biology and Frontier Project Life's Adaptation Strategies of Environmental Changes, Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan.
authors.forename: Osami
authors.initials: O
authors.lastname: Misumi
authors.forename: Motomichi
authors.initials: M
authors.lastname: Matsuzaki
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Nozaki
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Miyagishima
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mori
authors.forename: Keiji
authors.initials: K
authors.lastname: Nishida
authors.forename: Fumi
authors.initials: F
authors.lastname: Yagisawa
authors.forename: Yamato
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Haruko
authors.initials: H
authors.lastname: Kuroiwa
authors.forename: Tsuneyoshi
authors.initials: T
authors.lastname: Kuroiwa
mesh_terms: D020418:Algal Proteins / Q000235:genetics; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D019143:Evolution, Molecular; D016678:Genome; D015388:Organelles / Q000235:genetics* / Q000378:metabolism*; D010788:Photosynthesis; D010802:Phylogeny; D000461:Rhodophyta / Q000235:genetics* / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D020418:Algal Proteins