RT Journal Article SR Electronic T1 SYP-3 Restricts Synaptonemal Complex Assembly to Bridge Paired Chromosome Axes During Meiosis in Caenorhabditis elegans JF Genetics JO Genetics FD Genetics Society of America SP 2015 OP 2025 DO 10.1534/genetics.107.072413 VO 176 IS 4 A1 Smolikov, Sarit A1 Eizinger, Andreas A1 Schild-Prufert, Kristina A1 Hurlburt, Allison A1 McDonald, Kent A1 Engebrecht, JoAnne A1 Villeneuve, Anne M. A1 Colaiácovo, Mónica P. YR 2007 UL http://www.genetics.org/content/176/4/2015.abstract AB Synaptonemal complex (SC) formation must be regulated to occur only between aligned pairs of homologous chromosomes, ultimately ensuring proper chromosome segregation in meiosis. Here we identify SYP-3, a coiled-coil protein that is required for assembly of the central region of the SC and for restricting its loading to occur only in an appropriate context, forming structures that bridge the axes of paired meiotic chromosomes in Caenorhabditis elegans. We find that inappropriate loading of central region proteins interferes with homolog pairing, likely by triggering a premature change in chromosome configuration during early prophase that terminates the search for homologs. As a result, syp-3 mutants lack chiasmata and exhibit increased chromosome missegregation. Altogether, our studies lead us to propose that SYP-3 regulates synapsis along chromosomes, contributing to meiotic progression in early prophase.