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Main Title Stage-Specific Damage to Synaptonemal Complexes and Metaphase Chromosomes Induced by X Rays in Male Mouse Germ Cells.
Author Backer, L. C. ; Sontag, M. R. ; Allen, J. W. ;
CORP Author Environmental Health Research and Testing, Inc., Research Triangle Park, NC. ;Duke Univ. Medical Center, Durham, NC.;Health Effects Research Lab., Research Triangle Park, NC. Genetic Toxicology Div.
Publisher c1991
Year Published 1991
Report Number EPA-68-01-4456; EPA/600/J-91/040;
Stock Number PB91-182238
Additional Subjects Synaptonemal complex ; Chromosome aberrations ; Metaphase ; X rays ; Spermatozoa ; Mice ; Mutagens ; Deoxyribonucleic acids ; Cell cycle ; Electron microscopy ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB91-182238 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 12p
Synaptonemal complexes (SCs) reveal mutagen-induced effects in germ cell meiotic chromosomes. The study was aimed at characterizing relationships between SC and metaphase I chromosome damage following radiation exposure at various stages of spermatogenesis. Male mice were irradiated with doses of 0, 2, or 4 Gy, and spermatocytes were harvested at times consistent with earlier exposures as spermatogonial stem cells, preleptotene cells (premeiotic DNA synthesis), or meiotic prophase cells. After stem-cell exposure, twice as many rearrangements were observed in SCs as in metaphase I chromosomes. Irradiation during premeiotic DNA synthesis resulted in dose-related increases in SC breakage and rearrangements (including novel forms) and in metaphase chromosomal aberrations. Following prophase exposure, various types and levels of SC and metaphase damage were observed. Irradiation of zygotene cells led to high frequencies of chromosome multivalents in metaphase I without a correspondingly high level of damage in preceding prophase SCs. Thus, irradiation of premeiotic and meiotic cells results in variable relationships between SC and metaphase chromosome damage.