LOCALIZATION OF RECA-LIKE RECOMBINATION PROTEINS ON CHROMOSOMES OF THE LILY AT VARIOUS MEIOTIC STAGES

The Rad51 and Lim15 proteins of lily, which are homologs of the bacter ial RecA protein, were found on chromosomes in various stages of meiot ic prophase 1. The presence of both Rad51 and Lim15 proteins as discre te foci on leptotene and zygotene chromosomes and their colocalization suggest that meiotic recombination begins at the leptotene stage with the cooperation of these proteins and continues in zygotene. Localiza tion of the foci on or adjacent to the chromosomes suggests that these proteins bind to the chromatin loops that extend from the axial cores . The proteins in these foci may participate in the searching and pair ing of homologous DNA. sequences, as the RecA protein does. The differ ent pattern of localization of the Rad51 protein between the leptotene and pachytene stages and the absence of the Lim15 protein in the pach ytene stage suggest that the Rad51 protein plays different roles in th ese stages.