A time course analysis through diapause reveals dynamic temporal
patterns of microRNAs associated with endocrine regulation in the
butterfly Pieris napi
Abstract
Organisms inhabiting highly seasonal environments must cope with a wide
range of environmentally induced challenges. Many seasonal challenges
require extensive physiological modification to survive. In winter, to
survive extreme cold and limited resources, insects commonly enter
diapause, which is an endogenously derived dormant state associated with
minimized cellular processes and low energetic expenditure. Due to the
high degree of complexity involved in diapause, substantial cellular
regulation is required, of which our understanding primarily derives
from the transcriptome via messenger RNA expression dynamics. Here we
aim to advance our understanding of diapause by investigating microRNA
(miRNA) expression in diapausing and direct developing pupae of the
butterfly Pieris napi. We identified coordinated patterns of miRNA
expression throughout diapause in both head and abdomen tissues of
pupae, and via miRNA target identification, found several expression
patterns to be enriched for relevant diapause-related physiological
processes. We also identified two candidate miRNAs, miR-14-5p and
miR-2a-3p, that are likely involved in diapause progression through the
ecdysone synthesis pathway, a critical regulator of diapause
termination. miR-14-5p targets phantom, a gene in the ecdysone synthesis
pathway, and miR-2a-3p, which has been found to be expressed in response
to ecdysone. Together, the expression patterns of these two miRNAs match
our current understanding of the timing of hormonal regulation of
diapause in P. napi and provide interesting candidates to further
explore the mechanistic role of microRNAs in diapause regulation.