title: Mouse CCDC79 (TERB1) is a meiosis-specific telomere associated protein.
abstract: BACKGROUND
  Telomeres have crucial meiosis-specific roles in the orderly reduction of chromosome numbers and in ensuring the integrity of the genome during meiosis. One such role is the attachment of telomeres to trans-nuclear envelope protein complexes that connect telomeres to motor proteins in the cytoplasm. These trans-nuclear envelope connections between telomeres and cytoplasmic motor proteins permit the active movement of telomeres and chromosomes during the first meiotic prophase. Movements of chromosomes/telomeres facilitate the meiotic recombination process, and allow high fidelity pairing of homologous chromosomes. Pairing of homologous chromosomes is a prerequisite for their correct segregation during the first meiotic division. Although inner-nuclear envelope proteins, such as SUN1 and potentially SUN2, are known to bind and recruit meiotic telomeres, these proteins are not meiosis-specific, therefore cannot solely account for telomere-nuclear envelope attachment and/or for other meiosis-specific characteristics of telomeres in mammals.
  
  
  RESULTS
  We identify CCDC79, alternatively named TERB1, as a meiosis-specific protein that localizes to telomeres from leptotene to diplotene stages of the first meiotic prophase. CCDC79 and SUN1 associate with telomeres almost concurrently at the onset of prophase, indicating a possible role for CCDC79 in telomere-nuclear envelope interactions and/or telomere movements. Consistent with this scenario, CCDC79 is missing from most telomeres that fail to connect to SUN1 protein in spermatocytes lacking the meiosis-specific cohesin SMC1B. SMC1B-deficient spermatocytes display both reduced efficiency in telomere-nuclear envelope attachment and reduced stability of telomeres specifically during meiotic prophase. Importantly, CCDC79 associates with telomeres in SUN1-deficient spermatocytes, which strongly indicates that localization of CCDC79 to telomeres does not require telomere-nuclear envelope attachment.
  
  
  CONCLUSIONS
  CCDC79 is a meiosis-specific telomere associated protein. Based on our findings we propose that CCDC79 plays a role in meiosis-specific telomere functions. In particular, we favour the possibility that CCDC79 is involved in telomere-nuclear envelope attachment and/or the stabilization of meiotic telomeres. These conclusions are consistent with the findings of an independently initiated study that analysed CCDC79/TERB1 functions.
authors.forename: Katrin
authors.initials: K
authors.lastname: Daniel
authors.forename: Daniel
authors.initials: D
authors.lastname: Tränkner
authors.forename: Lukasz
authors.initials: L
authors.lastname: Wojtasz
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shibuya
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Manfred
authors.initials: M
authors.lastname: Alsheimer
authors.affiliation: Institute of Physiological Chemistry, Technische Universität Dresden, Fiedlerstr, 42, Dresden 01307, Germany. attila.toth@mailbox.tu-dresden.de.
authors.forename: Attila
authors.initials: A
authors.lastname: Tóth
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism; D008297:Male; D008540:Meiosis; D051379:Mice; D008810:Mice, Inbred C57BL; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016615:Telomere / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; C464932:SUN1 protein, mouse; C587999:TERB1 protein, mouse