Marchetti F, Lowe X, Bishop J, Wyrobek A J
Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
Environ Mol Mutagen. 1997;30(4):410-7. doi: 10.1002/(sici)1098-2280(1997)30:4<410::aid-em6>3.0.co;2-m.
The objectives of this research were: 1) to investigate the time course of the cytogenetic defects induced by acrylamide (AA) treatment (5 x 50 mg/kg) of male germ cells in first-cleavage zygote metaphases using PAINT/DAPI analysis, and 2) to characterize the correlation between chromosomal aberrations at first cleavage, dominant lethality, and heritable translocations. PAINT/DAPI analysis employs multicolor fluorescence in situ hybridization painting plus DAPI staining to detect both stable and unstable chromosomal aberrations at first-cleavage metaphase of the zygote. High levels of chromosomally defective zygotes were detected after mating at all postmeiotic stages (20-190-fold, P < 0.001). Early spermatozoa (6.5 d post-treatment) were the most sensitive, with 76% of the zygotes carrying cytogenetic defects. A significant 10-fold increase was also detected 27.5 d post-treatment, indicating that AA had a cytogenetic effect on meiotic stages. PAINT/DAPI analysis revealed that: 1) AA-induced chromosomal breaks occurred at random, and 2) the frequencies of symmetrical and asymmetrical exchanges were similar at all mating days, except 9.5 d after AA treatment, where significantly (P < 0.02) more asymmetrical aberrations were found. Furthermore, the proportions of zygotes carrying unstable and stable chromosomal aberrations followed a similar post-treatment time course as the proportions of dominant lethality among embryos and heritable translocations among offspring. These findings indicate that PAINT/DAPI analysis of zygotic metaphases is a promising method for detecting male germ cell mutagens capable of inducing chromosomal aberrations and for evaluating the associated risks for embryonic loss and balanced translocations at birth.
1）使用PAINT/DAPI分析，研究丙烯酰胺（AA）处理（5×50mg/kg）雄性生殖细胞后，在第一次卵裂合子中期诱导的细胞遗传学缺陷的时间进程；2）表征第一次卵裂时的染色体畸变、显性致死率和可遗传易位之间的相关性。PAINT/DAPI分析采用多色荧光原位杂交染色加DAPI染色，以检测合子第一次卵裂中期的稳定和不稳定染色体畸变。在所有减数分裂后阶段交配后，均检测到高水平的染色体缺陷合子（20 - 190倍，P < 0.001）。早期精子（处理后6.5天）最敏感，76%的合子携带细胞遗传学缺陷。在处理后27.5天也检测到显著的10倍增加，表明AA对减数分裂阶段有细胞遗传学效应。PAINT/DAPI分析显示：1）AA诱导的染色体断裂随机发生；2）除AA处理后9.5天外，在所有交配日对称和不对称交换的频率相似，在该时间点发现显著更多的不对称畸变（P < 0.02）。此外，携带不稳定和稳定染色体畸变的合子比例，与胚胎中的显性致死率和后代中的可遗传易位比例，遵循相似的处理后时间进程。这些发现表明，对合子中期进行PAINT/DAPI分析，是一种有前景的方法，可用于检测能够诱导染色体畸变的雄性生殖细胞诱变剂，并评估出生时胚胎丢失和平衡易位的相关风险。
