title: Alleles of afd1 dissect REC8 functions during meiotic prophase I.
abstract: REC8 is a master regulator of chromatin structure and function during meiosis. Here, we dissected the functions of absence of first division (afd1), a maize rec8/alpha-kleisin homolog, using a unique afd1 allelic series. The first observable defect in afd1 mutants is the inability to make a leptotene chromosome. AFD1 protein is required for elongation of axial elements but not for their initial recruitment, thus showing that AFD1 acts downstream of ASY1/HOP1. AFD1 is associated with the axial and later the lateral elements of the synaptonemal complex. Rescuing 50% of axial element elongation in the weakest afd1 allele restored bouquet formation demonstrating that extent of telomere clustering depends on axial element elongation. However, rescuing bouquet formation was not sufficient for either proper RAD51 distribution or homologous pairing. It provides the basis for a model in which AFD1/REC8 controls homologous pairing through its role in axial element elongation and the subsequent distribution of the recombination machinery independent of bouquet formation.
authors.affiliation: Department of Molecular and Cell Biology, University California, Berkeley, CA 94720, USA.
authors.forename: Inna N
authors.initials: IN
authors.lastname: Golubovskaya
authors.forename: Olivier
authors.initials: O
authors.lastname: Hamant
authors.forename: Ljuda
authors.initials: L
authors.lastname: Timofejeva
authors.forename: Chung-Ju Rachel
authors.initials: CJ
authors.lastname: Wang
authors.forename: David
authors.initials: D
authors.lastname: Braun
authors.forename: Robert
authors.initials: R
authors.lastname: Meeley
authors.forename: W Zacheus
authors.initials: WZ
authors.lastname: Cande
mesh_terms: D000483:Alleles; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D023902:Chromosome Pairing; D032461:Chromosomes, Plant / Q000235:genetics*; D049469:Meiotic Prophase I / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D051135:Rad51 Recombinase / Q000378:metabolism; D003313:Zea mays / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; D010940:Plant Proteins; D051135:Rad51 Recombinase