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SYNAPTONEMAL COMPLEX ANALYSIS OF MUTAGEN EFFECTS ON MEIOTIC CHROMOSOME STRUCTURE AND BEHAVIOR
Citation:
Allen, J.W., P. Poorman-Allen, L. Backer, B. Westbrook-Collins, AND M. Moses. SYNAPTONEMAL COMPLEX ANALYSIS OF MUTAGEN EFFECTS ON MEIOTIC CHROMOSOME STRUCTURE AND BEHAVIOR. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-90/167.
Description:
Homologous chromosome synapsis and crossing-over at meiosis are basic to mammalian gamete development. hey achieve genetic recombination, regulate chromosome segregation, and are believed to function in repair and maturation. ynaptonemal complexes (SCs) are axial correlates of meiotic chromosome bivalent and develop in conjunction with homologous chromosome synapsis. t is shown here that various mutagens/anti-mitotic agents-cyclophosphamide (alkylating agent), colchicine (anti-tubulin alkaloid), amacrine or m-AMSA (topoisomerase inhibitor), bleomycin (radiomimetic agent), and gamma radiation-induce diverse structural and synaptic errors in SCs of treated mice and hamsters. onventional types of clastogenic effects as well as damage unique to meiotic prophase appear to be manifested in the SC. istinctive patterns of damage are associated with specific mutagenic agents/mechanisms. ome SC aberrations are suggestive of a site specificity possibly related to crossing-over. ollowing treatments at premeiotic (ultimate) S phase, higher levels of damage are typically recovered from prophase SCs than from meiotic metaphase chromosomes, thereby indicating that intervening cell loss or repair processes may have occurred. he sensitivity of SC analysis for studies of meiotic prophase chromosomes allows the detection of structural/behavioral abnormalities that are otherwise unapparent. he significance of SC abnormalities lies in their implications for developmental and genetic impairment, which may result in gamete.