Meeting Abstract
P1.58 Saturday, Jan. 4 15:30 Do HDACs regulate Sarcophaga bullata pupal diapause? REYNOLDS, J. A.*; DENLINGER, D. L.; Ohio State University; Ohio State University reynolds.473@osu.edu
Histone deacetylases (HDACs) remove acetyl groups from histone and non-histone protein and are important for a variety of biological processes including gene transcription, cell-cycle regulation, environmental sensing, and stress-response. We tested the hypothesis that HDACs regulate pupal diapause in the flesh fly, S. bullata, by measuring differences in HDAC gene expression and enzyme activity in pre-diapause and diapause flies compared to their non-diapause counterparts. We also measured gene expression and enzyme activity in pupae treated with hexane to terminate diapause to determine a possible role for HDACs in post-diapause development. Transcripts of 4 genes encoding HDACs (rpd3/hdac1, hdac3, hdac6, and sirtuin2(sirt2)) were up to 2-fold more abundant in diapause-destined 1st instars, which suggests a role for these genes in programming diapause entry. Transcripts of hdac3, hdac6, and sirt2 were 60, 45, and 30 % lower, respectively, in diapausing pupae compared to non-diapause pupae; there was no difference in the mRNA abundance of rpd3/hdac1. Thus, it is unlikely that these genes are required for diapause maintenance. There was also no difference in mRNA abundance of rpd3/hdac1 24 h after diapause was terminated with hexane. Hdac3, hdac6, and sirt2 were significantly upregulated, up to 3-fold, during this time, and they likely regulate post-diapause development. HDAC enzyme activity was significantly reduced by ~ 60% in diapausing pupae compared to non-diapause flies. After diapause was terminated, HDAC activity remained at a low level for 24 h, but increased so that activity was equivalent to non-diapause pupae by 48 h post-termination. Taken together, our data suggest HDACs participate in diapause initiation and are necessary for post-diapause development, but they are not predicted to have a role in maintaining diapause.
