The chimera assay is a sensitive test for detecting in vivo exposure of the mammalian germ cell to ionizing radiation. This exposure results in a cell proliferation disadvantage that is expressed in cultured mouse preimplantation embryos. In the assay, 4-cell embryos from non-exposed parents are paired with 4-cell embryos from either exposed male or female parents to form aggregation chimeras. The assay's endpoint is a """"""""proliferation ratio"""""""", which is the number of cells contributed by the experimental partner embryo divided by the total number of cells comprising a chimera after 2-3 rounds of cell division. Ratios significantly less than 0.5 indicate than an experimental partner embryo expressed a cell proliferation disadvantage in the chimera. Progeny cells from the two partner embryos are currently distinguished by labelling the control partner embryo with the cytoplasmic dye FITC prior to chimera construction. However, label dilution from successive cell divisions precludes postimplantation analyses and heritability tests. This project's objective is to develop an 'enhanced' chimera assay to examine the effects of parental germ cell exposure in the male that persist beyond implantation and birth. Our First Specific Aim is to incorporate a heritable non-expressing transgenic cell lineage marker to replace the short-term cell lineage marker FITC in the chimera assay. The Second Specific Aim is to use our transgenic cell lineage marker to extend the chimera assay into postimplantation analyses of fetal and postnatal development. The Third Specific Aim is to apply the chimera assay with the transgenic cell lineage marker for heritability testing after parental exposure to reproductive toxicants.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
1R01ES006516-01
Application #
3254755
Study Section
Radiation Study Section (RAD)
Project Start
1993-08-01
Project End
1997-07-31
Budget Start
1993-08-01
Budget End
1994-07-31
Support Year
1
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of California Davis
Department
Type
Schools of Earth Sciences/Natur
DUNS #
094878337
City
Davis
State
CA
Country
United States
Zip Code
95618
Baulch, Janet E; Li, Ming-Wen; Raabe, Otto G (2007) Effect of ATM heterozygosity on heritable DNA damage in mice following paternal F0 germline irradiation. Mutat Res 616:34-45
Baulch, Janet E; Raabe, Otto G (2005) Gamma irradiation of Type B spermatogonia leads to heritable genomic instability in four generations of mice. Mutagenesis 20:337-43
Baulch, Janet E; Raabe, Otto G; Wiley, Lynn M et al. (2002) Germline drift in chimeric male mice possessing an F2 component with a paternal F0 radiation history. Mutagenesis 17:9-13
Vance, M M; Baulch, J E; Raabe, O G et al. (2002) Cellular reprogramming in the F3 mouse with paternal F0 radiation history. Int J Radiat Biol 78:513-26
Baulch, J E; Raabe, O G; Wiley, L M (2001) Heritable effects of paternal irradiation in mice on signaling protein kinase activities in F3 offspring. Mutagenesis 16:17-23
Lum, R M; Wiley, L M; Barakat, A I (2000) Influence of different forms of fluid shear stress on vascular endothelial TGF-beta1 mRNA expression. Int J Mol Med 5:635-41
Vance, M M; Wiley, L M (1999) Gap junction intercellular communication mediates the competitive cell proliferation disadvantage of irradiated mouse preimplantation embryos in aggregation chimeras. Radiat Res 152:544-51
Burruel, V R; Raabe, O G; Wiley, L M (1997) In vitro fertilization rate of mouse oocytes with spermatozoa from the F1 offspring of males irradiated with 1.0 Gy 137Cs gamma-rays. Mutat Res 381:59-66
Wiley, L M; Baulch, J E; Raabe, O G et al. (1997) Impaired cell proliferation in mice that persists across at least two generations after paternal irradiation. Radiat Res 148:145-51