Leptotene/Zygotene chromosome movement via the SUN/KASH protein bridge in Caenorhabditis elegans

The caenorhabditis elegans inner nuclear envelope protein matefin/sun-1 plays a conserved,pivotal role in the process of genome haploidization. chk-2-dependent phosphorylation of sun-1 regulates homologous chromosome pairing and interhomolog recombination in caenorhabditis elegans. using time-lapse microscopy,we characterized the movement of matefin/sun-1::gfp aggregates (the equivalent of chromosomal attachment plaques) and showed that the dynamics of matefin/sun-1 aggregates remained unchanged throughout leptonene/zygotene,despite the progression of pairing. movement of sun-1 aggregates correlated with chromatin polarization. we also analyzed the requirements for the formation of movement-competent matefin/sun-1 aggregates in the context of chromosome structure and found that chromosome axes were required to produce wild-type numbers of attachment plaques. abrogation of synapsis led to a deceleration of sun-1 aggregate movement. analysis of matefin/sun-1 in a double-strand break deficient mutant revealed that repair intermediates influenced matefin/sun-1 aggregate dynamics. investigation of movement in meiotic regulator mutants substantiated that proper orchestration of the meiotic program and effective repair of dna double-strand breaks were necessary for the wild-type behavior of matefin/sun-1 aggregates. © 2010 baudrimont et al.