Figure 4
Comparative analysis of SPO11-homologues. (A) Multiple sequence alignment of motifs I to V of SPO11. The bold tyrosine (Y) residue with an asterisk in motif I is the putative active center for covalent bonding to the 5' termini of cleaved DNA upon meiotic double-stranded cleavage. The triple asterisk in motif V indicates the conserved DXD sequence (see text). Underlined sequences were used for phylogenetic analyses. (B) Schematic diagrams of the genomic structures of OsSPO11 genes. Black boxes, coding regions; grey boxes, untranslated regions; solid lines, introns. Arrows indicate primers for real-time RT-PCR analyses. (C) Phylogenetic analyses of the amino acid sequences of motifs I-V. A neighbor-joining (NJ) tree was constructed using ClustalX ver. 2.0. Aga, Anopheles gambiae (EAA05541); Ago, Ashbya gossypii (AAS51945); Am, Apis mellifera (XP_001122679); Ap, Aeropyrum pernix (BAA79679); At1, Arabidopsis thaliana (CAB81544); At2, A. thaliana (CAB81545); At3, A. thaliana (ABI54341); Ca, Candida albicans (EAK95423); Dm, Drosophila melanogaster (AAC61735); Dr, Danio rerio (NP_991245); Dv, Drosophila virilis (EDW61133); Gg, Gallus gallus (XP_001232076); Gz, Gibberella zeae (XP_386125); Hs, Homo sapiens (AAD52562); Hw, Haloquadratum walsbyi (CAJ52765); Mj, Methanocaldococcus jannaschii (Q57815); Mm, Mus musculus (AAD52563); Nc, Neurospora crassa (CAB88597); Nv, Nematostella vectensis (EDO44118); Ol2, Ostreococcus lucimarinus (ABO99188); Ol3, O. lucimarinus (ABO95960); OsA, OsSPO11A; OsB, OsSPO11B; OsC, OsSPO11C; OsD, OsSPO11D; Pa, Podospora anserina (CAP73361); Pp1, Physcomitrella patens (EDQ80601); Pp2, P. patens (EDQ56207); Pp3, P. patens (EDQ71569); Ps, Pichia stipitis (XP_001384151); Pt1, Populus trichocarpa (EEE85181); Pt3, P. trichocarpa (EEE71999); Rc1, Ricinus communis (EEF39612); Rc3, R. communis (EEF37163); Sb1, Sorghum bicolor (EER93438); Sb2, S. bicolor (EES14573); Sb3, S. bicolor (EER95053); Sc, Saccharomyces cerevisiae (AAA65532); Sp, Schizosaccharomyces pombe (CAB11511); Ss, Sulfolobus shibatae (CAA71605); Tg, Taeniopygia guttata (XP_002195778); Tn, Thermoproteus neutrophilus (ACB40317); Xt, Xenopus tropicali s (AAH80352). The entire sequences of these SPO11 homologues are shown in Additional File 1 Figure S1.