title: Telomere distribution pattern and synapsis initiation during spermatogenesis in zebrafish.
abstract: BACKGROUND
  Telomeres are located at ends of eukaryotic chromosomes and can affect proper chromosomal positioning. During spermatogenesis, the appropriate dynamics and behavior of chromosomes is crucial to generate haploid cells through meiosis. Here, we describe telomere distribution patterns during spermatogenesis in zebrafish, especially during meiotic prophase I, using fluorescence in situ hybridization. This was combined with synaptonemal complex protein 3 immunostaining, which allows the staging of spermatocytes.
  
  
  RESULTS
  During spermatogonial proliferation and the preleptotene stage, telomeres were dispersed throughout the nucleus. During the leptotene stage, telomeres temporarily moved to one pole of the nucleus at which γ-tubulin was located, forming the telomere bouquet. The cluster lasted until the onset of zygotene where it coincided with terminal synapsis initiation. They then spread around the periphery of the nucleus during the zygotene to pachytene stages. During postmeiotic stages, telomeres in spermatids and sperm were again dispersed throughout the nuclei. Application of this procedure in meiotic mutants confirmed that meiotic telomere clustering is independent of axial element formation of the synaptonemal complex.
  
  
  CONCLUSIONS
  These data clearly showed the clustering and distributions of telomeres throughout spermatogenesis in zebrafish. This procedure could be used to screen for mutants that have primary defects in telomere clustering.
authors.affiliation: Genetic Strains Research Center, National Institute of Genetics, Mishima, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Saito
authors.forename: Chiharu
authors.initials: C
authors.lastname: Sakai
authors.forename: Toshihiroa
authors.initials: T
authors.lastname: Kawasaki
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Sakai
mesh_terms: D000818:Animals; D023902:Chromosome Pairing / Q000502:physiology*; D017931:DNA Primers / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D011418:Prophase / Q000502:physiology; D013091:Spermatogenesis / Q000502:physiology*; D016615:Telomere / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism; D015027:Zebrafish / Q000502:physiology*; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: D017931:DNA Primers; C000588551:Sycp1 protein, zebrafish; D014404:Tubulin; D029961:Zebrafish Proteins
keywords: Sycp3; meiosis; meiotic mutant; telomere bouquet