170 Acetylation patterns of histone H3K27 in aged pig oocytes
K. Sprungl A , H. Arena A , S. Reynolds A and B. Whitaker AA University of Findlay, Findlay, OH, USA
Reproduction, Fertility and Development 34(2) 323-323 https://doi.org/10.1071/RDv34n2Ab170
Published: 7 December 2021
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Fertilisation and subsequent embryonic development of aged oocytes is not as successful due to changes in the proteins and genetic material. Aging of oocytes causes a wide variation of epigenetic modifications to the DNA and its proteins (histones). Universal deacetylation of the histones for meiotic progress is widely disputed, in part due to the diverse nature of the number and nature of histones and their lysine residues in the genome. Histone H3K27 is linked to the activation of various developmental genes but has not been widely studied during oocyte maturation, before fertilisation. Therefore, the objective of this study was to determine the acetylation patterns of H3K27 in porcine oocytes during maturation using an in vitro aging model. Oocytes were randomly assigned to either 40 h of maturation (normal length) or 64 h of maturation (extended length) and supplemented with trichostatin A (TSA; 0 or 100 ng mL−1) for the first 24 h in the normal length group and the first 48 h in the extended length group (maturation 1). In either length, the final 16 h of maturation was without TSA (maturation 2). Oocytes (n = 40) had their cumulus cells and zona pellucidae removed at the end of maturation 1 or 2 and were then permeabilised and fixed before immunofluorescence of H3K27 acetylation. This experiment was a 2 × 2 factorial design and analysed by two-way ANOVA using the GLM procedure. Oocytes supplemented with TSA showed significantly greater (P < 0.05) acetylation at H3K27 than oocytes matured without TSA. Oocytes matured for an extended length had significantly greater (P < 0.05) acetylation at H3K27 than oocytes matured for the normal length of time. There was a significant (P < 0.05) TSA × length interaction: acetylation at H3K27 increased with time and TSA supplementation. These results suggest that an increase in oocyte maturation time increases H3K27 acetylation, similar to the effects of supplementing a histone deacetylase inhibitor such as TSA.
