Brief exposure to warm temperatures reduces intron retention in Kdm6b in a species with temperature-dependent sex determination

Animals with temperature-dependent sex determination (TSD) respond to
thermal cues during early embryonic development to trigger gonadal
differentiation. TSD has primarily been studied using constant temperature
incubations, where embryos are exposed to constant male- or
female-producing temperatures and these studies have identified genes that
display sex-specific expression in response to incubation temperature.
Kdm6b, a histone demethylase, has received specific attention as it is
among the initial genes to respond to incubation temperature and is
necessary for testis development. Interestingly, Kdm6b retains an intron
when eggs are incubated at a constant male-producing temperature, but the
role of thermal variability in this developmental process is relatively
understudied. Species with TSD regularly experience thermal cues that
fluctuate between male- and female-producing temperatures throughout
development but it is unclear how Kdm6b responds to such variable
temperatures. In this study, we investigate temperature sensitive splicing
in Kdm6b by exposing embryos to male- and female-promoting thermal
conditions. We show a rapid decrease in levels of the intron retaining
transcript of Kdm6b upon exposure to female-producing conditions. These
results demonstrate that, under ecologically relevant conditions,
temperature sensitive splicing can differentially regulate genes critical
to TSD.