The Chromodomain Protein MRG-1 Facilitates SC-Independent Homologous Pairing during Meiosis in Caenorhabditis elegans

• Published in: Developmental cell Vol. 21; no. 6; pp. 1092 - 1103
• Main Authors: Dombecki, Carolyn R., Chiang, Ason C.Y., Kang, Hyun-Joo, Bilgir, Ceyda, Stefanski, Nicholas A., Neva, Bryan J., Klerkx, Elke P.F., Nabeshima, Kentaro
• Format: Journal Article
• Language: English
• Published: Cambridge, MA Elsevier Inc 13.12.2011; Cell Press
• Subjects: Animals; Animals, Genetically Modified; Biological and medical sciences; Caenorhabditis elegans - cytology; Caenorhabditis elegans - genetics; Caenorhabditis elegans - metabolism; Caenorhabditis elegans Proteins - genetics; Caenorhabditis elegans Proteins - metabolism; Cell cycle, cell proliferation; Cell differentiation, maturation, development, hematopoiesis; Cell physiology; Chromosome Pairing - genetics; Chromosome Pairing - physiology; Fundamental and applied biological sciences. Psychology; Genes, Helminth; Meiosis - genetics; Meiosis - physiology; Molecular and cellular biology; Mutation; Synaptonemal Complex - genetics; Synaptonemal Complex - metabolism; Caenorhabditis elegans; Helmintha; Development; Nemathelminthia; Meiosis; Invertebrata; Nematoda; Pairing; Protein
• ISSN: 1534-5807; 1878-1551
• DOI: 10.1016/j.devcel.2011.09.019

Homologous chromosome pairing is a prerequisite to establish physical linkage between homologs, which is critical for faithful chromosome segregation during meiosis I. The establishment of pairing is genetically separable from subsequent synapsis, defined as stabilization of pairing by the synaptonemal complex (SC). The underlying mechanism of presynaptic pairing is poorly understood. In the nematode Caenorhabditis elegans, a unique cis-acting element, the pairing center (PC), is essential for presynaptic pairing; however, it is not known whether and how the remainder of the chromosome contributes to presynaptic pairing. Here we report direct evidence for presynaptic pairing activity intrinsic to non-PC regions, which is facilitated by a conserved chromodomain protein, MRG-1. In mrg-1 loss-of-function mutants, pairing is compromised specifically in non-PC regions, leading to nonhomologous SC assembly. Our data support a model in which presynaptic alignment in non-PC regions collaborates with initial PC pairing to ensure correct homologous synapsis. [Display omitted] ► MRG-1 facilitates pairing at the non-pairing center (PC) loci of autosomes ► Presynaptic alignment along the non-PC regions is supported by MRG-1 ► Homologous synapsis at the PC does not always lead to full synapsis in mrg-1 ► mrg-1 mutant exhibits nonhomologous synapsis specifically at the non-PC regions