Meeting Abstract
P1.50 Friday, Jan. 4 Do epigenetic mechanisms regulate diapause and the maternal block of diapause in the flesh fly, Sarcophaga bullata? REYNOLDS, JA*; DENLINGER , DL; Ohio State University; Ohio State University reynolds.473@osu.edu
Diapause, an alternative developmental pathway that provides a means to escape from predictable periods of harsh environmental conditions, is maternally regulated in many insects. Although non-genetic, maternal regulation of diapause is common, the molecular basis of these maternal effects are unknown. In the flesh fly, Sarcophaga bullata, the potential to enter diapause is blocked if the mother experienced diapause when she was a pupa. We tested the hypothesis that histone modifications and RNA-interference (RNAi), two types of epigenetic mechanisms that can alter phenotype without changing the DNA sequence, regulate diapause and the maternal block of pupal diapause in S. bullata. We used quantitative real-time PCR (qRT-PCR) to assess mRNA expression of 15 epigenetics-related genes. In photosensitive 1st instar larvae, the stage when diapause can be induced in this species, 7 epigenetics related genes, heterochromatin protein 1, su(var)3-9, su(var)3-3, piwi, spindle, histone deacetylase 1, and argonaute 2 are upregulated in larvae exposed to diapause-inducing conditions compared to larvae reared in diapause-averting conditions. Thus we predict these genes have a role in diapause initiation. We also predict that argonaute 1, which encodes an RNAi pathway component that is upregulated 2-fold in diapause pupae compared to non-diapause pupae, has a role in diapause maintenance. In addition, piwi, histone demethylase 4, and dicer1, are likely involved in the maternal block of diapause because mRNA expression of these genes is upregulated in pupal progeny of females with a diapause history compared to females with a non-diapause history. Taken together, our results reveal major differences in transcript abundance of several epigenetics-related genes and provide evidence that epigenetic mechanisms regulate diapause and the maternal block of diapause in S. bullata.
