Transcriptional Changes in the Ovaries of Perch from Chernobyl

Fish
have been highly exposed to radiation in freshwater systems
after the Chernobyl Nuclear Power Plant (NPP) accident in 1986 and
in freshwater and marine systems after the more recent Fukushima NPP
accident in 2011. In the years after the accident, the radioactivity
levels rapidly declined due to radioactive decay and environmental
processes, but chronic lower dose exposures persisted. To gain insights
into the long-term effects of environmental low dose radiation on
fish ovaries development, a high-throughput transcriptomic approach
including a de novo assembly was applied to different gonad phenotypes
of female perch: developed gonads from reference lakes, developed/irradiated
from medium contaminated lake, and both developed/irradiated and undeveloped
from more highly contaminated lakes. This is the most comprehensive
analysis to date of the gene responses in wildlife reproductive system
to radiation. Some gene responses that were modulated in irradiated
gonads were found to be involved in biological processes including
cell differentiation and proliferation (ggnb2, mod5, rergl), cytoskeleton organization
(k1C18, mtpn), gonad development
(nell2, tcp4), lipid metabolism
(ldah, at11b, nltp), reproduction (cyb5, cyp17A, ovos), DNA damage repair (wdhd1, rad51, hus1), and epigenetic mechanisms (dmap1). Identification
of these genes provides a better understanding of the underlying molecular
mechanisms underpinning the development of the gonad phenotypes of
wild perch and how fish may respond to chronic exposure to radiation
in their natural environment, though causal attribution of gene responses
remains unclear in the undeveloped gonads.