RESEARCH ARTICLE Synaptonemal complex assembly and H3K4Me3 demethylation determine DIDO3 localization in meiosis Ignacio Prieto & Anna Kouznetsova & Agnes Fütterer & Varvara Trachana & Esther Leonardo & Astrid Alonso Guerrero & Mercedes Cano Gamero & Cristina Pacios-Bras & Hervé Leh & Malcolm Buckle & Mónica Garcia-Gallo & Leonor Kremer & Antonio Serrano & Fernando Roncal & Juan Pablo Albar & José Luis Barbero & Carlos Martínez-A & Karel H. M. van Wely Received: 4 May 2009 / Accepted: 2 June 2009 # Springer-Verlag 2009 Abstract Synapsis of homologous chromosomes is a key meiotic event, mediated by a large proteinaceous structure termed the synaptonemal complex. Here, we describe a role in meiosis for the murine death-inducer obliterator (Dido) gene. The Dido gene codes for three proteins that recognize trimethylated histone H3 lysine 4 through their amino- terminal plant homeodomain domain. DIDO3, the largest of the three isoforms, localizes to the central region of the synaptonemal complex in germ cells. DIDO3 follows the distribution of the central region protein SYCP1 in Sycp3-/- spermatocytes, which lack the axial elements of the synaptonemal complex. This indicates that synapsis is a requirement for DIDO3 incorporation. Interestingly, DIDO3 is missing from the synaptonemal complex in Atm mutant spermatocytes, which form synapses but show persistent trimethylation of histone H3 lysine 4. In order to further address a role of epigenetic modifications in DIDO3 localization, we made a mutant of the Dido gene that produces a truncated DIDO3 protein. This truncated protein, which lacks the histone-binding domain, is incor- Chromosoma DOI 10.1007/s00412-009-0223-7 Communicated by S. Keeney I. Prieto : A. Fütterer : V. Trachana : E. Leonardo : A. Alonso Guerrero : M. Cano Gamero : C. Pacios-Bras : A. Serrano : C. Martínez-A : K. H. M. van Wely (*) Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus de Cantoblanco, 28049 Madrid, Spain e-mail: kvanwely@cnb.csic.es I. Prieto : J. L. Barbero Department of Cell and Developmental Biology, Centro de Investigaciones Biológicas/CSIC, Ramiro de Maetzu 6, 28040 Madrid, Spain A. Kouznetsova Department of Cell and Molecular Biology (CMB), Karolinska Institutet, Berzelius väg 35, 171 77 Stockholm, Sweden H. Leh : M. Buckle Laboratoire de Biotechnologies et de Pharmacologie génétique Appliquée (LBPA), CNRS/Ecole Normale Supérieure de Cachan, 61 Avenue du Président Wilson, 94235 Cachan, France M. Garcia-Gallo : L. Kremer Protein Tools Unit, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus de Cantoblanco, 28049 Madrid, Spain F. Roncal : J. P. Albar Department of Proteomics, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus de Cantoblanco, 28049 Madrid, Spain Present Address: V. Trachana Laboratory of Molecular and Cellular Aging, Institute of Biological Research and Biotechnology, 48 Vas. Constantinou Ave, Athens 11635, Greece Present Address: A. Serrano Servicio de Inmunología, Hospital 12 de Octubre, Avenida de Córdoba s/n, 28041 Madrid, Spain