Differential intron retention in Jumonji chromatin modifier genes is implicated in reptile temperature-dependent sex determination

Ira W. Deveson, Clare E. Holleley, James Blackburn, Jennifer A. Marshall Graves, John S. Mattick, Paul D. Waters, Arthur Georges

Research output: Contribution to journalArticle

42 Citations (Scopus)
3 Downloads (Pure)

Abstract

In many vertebrates, sex of offspring is determined by external environmental cues rather than by sex chromosomes. In reptiles, for instance, temperature-dependent sex determination (TSD) is common. Despite decades of work, the mechanism by which temperature is converted into a sex-determining signal remains mysterious. This is partly because it is difficult to distinguish the primary molecular events of TSD from the confounding downstream signatures of sexual differentiation. We use the Australian central bearded dragon, in which chromosomal sex determination is overridden at high temperatures to produce sex-reversed female offspring, as a unique model to identify TSD-specific features of the transcriptome. We show that an intron is retained in mature transcripts from each of two Jumonji family genes, JARID2 and JMJD3, in female dragons that have been sex-reversed by temperature but not in normal chromosomal females or males. JARID2 is a component of the master chromatin modifier Polycomb Repressive Complex 2, and the mammalian sex-determining factor SRY is directly regulated by an independent but closely related Jumonji family member. We propose that the perturbation of JARID2/JMJD3 function by intron retention alters the epigenetic landscape to override chromosomal sex-determining cues, triggering sex reversal at extreme temperatures. Sex reversal may then facilitate a transition from genetic sex determination to TSD, with JARID2/JMJD3 intron retention preserved as the decisive regulatory signal. Significantly, we also observe sex-associated differential retention of the equivalent introns in JARID2/JMJD3 transcripts expressed in embryonic gonads from TSD alligators and turtles, indicative of a reptile-wide mechanism controlling TSD.
Original languageEnglish
Article numbere1700731
Pages (from-to)1-9
Number of pages9
JournalScience Advances
Volume3
Issue number6
DOIs
Publication statusPublished - Jun 2017

Cite this