Enhanced micronucleus formation in the descendants of gamma-ray-irradiated tobacco cells: evidence for radiation-induced genomic instability in plant cells.
Ionizing radiation-induced genomic instability has been documented in various end points such as chromosomal aberrations and mutations, which arises in the descendants of irradiated mammalian or yeast cells many generations after the initial insult. This study aimed at addressing radiation-induced genomic instability in higher plant tobacco cells. We thus investigated micronucleus (MN) formation and cell proliferation in tobacco cells irradiated with gamma-rays and their descendants. In gamma-irradiated cells, cell cycle was arrested at G2/M phase at around 24 h post-irradiation but released afterward. In contrast, MN frequency peaked at 48 h post-irradiation. Almost half of 40 Gy-irradiated cells had MN at 48 h post-irradiation, but proliferated as actively as sham-irradiated cells up to 120 h post-irradiation. Moreover, the descendants that have undergone at least 22 generations after irradiation still showed a two-fold MN frequency compared to sham-irradiated cells. This is the direct evidence for radiation-induced genomic instability in tobacco cells.
Yokota
Yuichiro
Y
Life Science and Biotechnology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japan. yokota.yuichiro@jaea.go.jp
Funayama
Tomoo
T
Hase
Yoshihiro
Y
Hamada
Nobuyuki
N
Kobayashi
Yasuhiko
Y
Tanaka
Atsushi
A
Narumi
Issay
I
D002453:Cell Cycle / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D005720:Gamma Rays; D042822:Genomic Instability; D048629:Micronuclei, Chromosome-Defective / Q000528:radiation effects*; D013997:Time Factors; D014026:Nicotiana / Q000166:cytology / Q000235:genetics* / Q000528:radiation effects*