Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, BC, Canada V6H-3N1.
Reprod Biomed Online. 2012 Jan;24(1):91-100. doi: 10.1016/j.rbmo.2011.09.013. Epub 2011 Oct 7.
Disrupted meiotic behaviour of inversion carriers may be responsible for suboptimal sperm parameters in these carriers. This study investigated meiotic recombination, synapsis, transcriptional silencing and chromosome segregation effects in a pericentric inv(1) carrier. Recombination (MLH1), synapsis (SYCP1, SYCP3) and transcriptional inactivation (γH2AX, BRCA1) were examined by fluorescence immunostaining. Chromosome specific rates of recombination were determined by fluorescence in-situ hybridization. Furthermore, testicular sperm was examined for aneuploidy and segregation of the inv(1). Our findings showed that global recombination rates were similar to controls. Recombination on the inv(1) and the sex chromosomes were reduced. The inv(1) associated with the XY body in 43.4% of cells, in which XY recombination was disproportionately absent, and 94.3% of cells displayed asynapsed regions which displayed meiotic silencing regardless of their association with the XY body. Furthermore, a low frequency of chromosomal imbalance was observed in spermatozoa (3.4%). Our results suggest that certain inversion carriers may display unimpaired global recombination and impaired recombination on the involved and the sex chromosomes during meiosis. Asynapsis or inversion-loop formation in the inverted region may be responsible for impaired spermatogenesis and may prevent sperm-chromosome imbalance.
倒位携带者减数分裂行为的破坏可能是导致这些携带者精子参数不佳的原因。本研究调查了一种着丝粒倒位 inv(1)携带者的减数分裂重组、联会、转录沉默和染色体分离效应。通过荧光免疫染色检测重组（MLH1）、联会（SYCP1、SYCP3）和转录失活（γH2AX、BRCA1）。通过荧光原位杂交确定染色体特异性重组率。此外，还检查了睾丸精子的非整倍体和 inv(1)的分离。我们的研究结果表明，总体重组率与对照组相似。inv(1)和性染色体上的重组减少。在 43.4%的细胞中，inv(1)与 X-Y 体相关联，其中 X-Y 重组明显缺失，并且 94.3%的细胞显示出联会区，这些联会区表现出减数分裂沉默，无论它们是否与 X-Y 体相关联。此外，在精子中观察到染色体不平衡的频率较低（3.4%）。我们的结果表明，某些倒位携带者在减数分裂过程中可能表现出不受影响的总体重组和受影响的染色体和性染色体上的重组。倒位区域的非联会或倒位环形成可能是导致精子发生受损的原因，并可能防止精子染色体失衡。
