Analysis of replication protein A (RPA) in human spermatogenesis.
Replication protein A (RPA) has been identified as a component of early recombination nodules. It is thought to stimulate homologous pairing and strand exchange reactions. The expression pattern of RPA in human spermatocytes has been analysed using immunocytogenetic techniques on testicular biopsies from adult male patients. What appears to be connecting RPA-filaments was observed between as yet unsynapsed homologous regions at early stages of zygotene. RPA foci were also observed in synaptic segments at zygotene and early pachytene, in numbers that peak at the end of zygotene. The presence of a localization pattern for RPA was also detected, but statistical analysis of distances between adjacent RPA foci shows that this pattern does not always follow a gamma distribution. Finally, it was determined that RPA is absent from non-centromeric heterochromatin in chromosome 9. The observed bridge-like structure could be the visualization of a proposed pre-synaptic RPA role in the strand invasion that precedes the formation of a Holliday Junction. These observations strengthen the original pre-synaptic model, although the visualization of post-synaptic RPA foci may indicate the presence of a different role for this protein during homologous recombination.
Oliver-Bonet
Maria
M
Department of Medical Genetics, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada.
Campillo
Mercedes
M
Turek
Paul J
PJ
Ko
E
E
Martin
R H
RH
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000328:Adult; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D011508:Chondroitin Sulfate Proteoglycans / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D002877:Chromosomes, Human / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D049469:Meiotic Prophase I; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D051716:Replication Protein A / Q000235:genetics / Q000378:metabolism*; D013090:Spermatocytes / Q000378:metabolism; D013091:Spermatogenesis
D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D011508:Chondroitin Sulfate Proteoglycans; D002868:Chromosomal Proteins, Non-Histone; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D051716:Replication Protein A; C492318:SMC3 protein, human; D000070957:MutL Protein Homolog 1