Meiotic telomere protein Ndj1p is required for meiosis-specific telomere distribution, bouquet formation and efficient homologue pairing

We have investigated the requirements for NDJ1 in meiotic telomere redistri bution and clustering in synchronized cultures of Saccharomyces cerevisiae. On induction of wild-type meiosis, telomeres disperse from premeiotic aggr egates over the nuclear periphery, and then cluster near the spindle pole b ody (bouquet arrangement) before dispersing again. In ndj1 Delta meiocytes, telomeres are scattered throughout the nucleus and fail to form perinuclea r meiosis-specific distribution patterns, suggesting that Ndj1p may functio n to tether meiotic telomeres to the nuclear periphery. Since ndj1 Delta me iocytes fail to cluster their telomeres at any prophase stage, Ndj1p is the first protein shown to be required for bouquet formation in a synaptic org anism. Analysis of homologue pairing by two-color fluorescence in situ hybr idization with cosmid probes to regions on III, IX, and XI revealed that di sruption of bouquet formation is associated with a significant delay (>2 h) of homologue pairing. An increased and persistent fraction of ndj1 Delta m eiocytes with Zip1p polycomplexes suggests that chromosome polarization is important for synapsis progression. Thus, our observations support the hypo thesis that meiotic telomere clustering contributes to efficient homologue alignment and synaptic pairing. Under naturally occurring conditions, bouqu et formation may allow for rapid sporulation and confer a selective advanta ge.