title: Selective decrease of chick embryonic primordial germ cells in vivo and in vitro by soft X-ray irradiation.
abstract: The feasibility of soft (low-energy) X-ray irradiation as a means of depleting the endogenous primordial germ cell(s) (PGC) of chicken embryos, to improve the efficiency of germ cell-mediated transgenesis, was investigated. Eggs were subjected to a non-irradiated control treatment and embryos were exposed for 40s to soft X-ray at 15, 16.5, or 18 kV ( approximately 1.5, 1.65, and 1.8 Gy, respectively). Exposure of stage X embryos to each dose of X-ray resulted in a reduction of approximately 50% in the number of PGC apparent at stage 28, whereas the total number of gonadal cells was unaffected. Irradiation (16.5 kV) of embryos at stage 9 or 14 also resulted in similar decreases in the number of PGC with no effect on the total number of gonadal cells. Irradiation did not affect embryo hatchability, compared with the non-irradiated control treatment, although the hatch rate increased with the age of embryos at the time of irradiation. Exposure of gonadal cells isolated from stage 28 embryos to X-ray (16.5 kV, approximately 0.8 Gy) prevented the increase in PGC number during subsequent culture for 10 days; the increase in the total number of gonadal cells was not affected. In conclusion, exposure of chicken embryos to a low dose of soft X-rays is effective for depleting the endogenous PGC population without affecting embryo hatchability or somatic cell viability.
authors.affiliation: Department of Food and Animal Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Jeong M
authors.initials: JM
authors.lastname: Lim
authors.forename: Huck M
authors.initials: HM
authors.lastname: Kwon
authors.forename: Duk K
authors.initials: DK
authors.lastname: Kim
authors.forename: Jin N
authors.initials: JN
authors.lastname: Kim
authors.forename: Tae S
authors.initials: TS
authors.lastname: Park
authors.forename: Tamao
authors.initials: T
authors.lastname: Ono
authors.forename: Jae Y
authors.initials: JY
authors.lastname: Han
mesh_terms: D000818:Animals; D002642:Chick Embryo / Q000502:physiology / Q000528:radiation effects*; D047108:Embryonic Development / Q000502:physiology / Q000528:radiation effects; D005260:Female; D005854:Germ Cells / Q000528:radiation effects*; D008297:Male; D011827:Radiation; D014965:X-Rays