Lineage-specific expression of heterochromatin protein 1γ in post-compaction, in vitro-produced bovine embryos
Corey Heffernan A , Penny A. F. Whiley A , Antonia Milionis A , Paul J. Verma A , Michael K. Holland A B , David A. Jans B C and Nancy T. D’Cruz A DA Monash Institute of Medical Research, Monash University, 27-31 Wright Street, Clayton, Vic. 3168, Australia.
B Australian Research Council (ARC) Centre of Excellence for Biotechnology and Development, Monash University, Vic. 3800, Australia.
C Department of Biochemistry and Molecular Biology, Monash University, Vic. 3800, Australia.
D Corresponding author. Email: nancy.dcruz@med.monash.edu.au
Reproduction, Fertility and Development 22(6) 1022-1031 https://doi.org/10.1071/RD09265
Submitted: 28 October 2009 Accepted: 1 February 2010 Published: 1 July 2010
Abstract
Heterochromatin protein 1γ (HP1γ) is a highly conserved regulator of euchromatic and heterochromatic gene expression. Mammalian HP1γ is essential for both successful preimplantation embryo development and maintenance of pluripotency in embryonic stem cells in vitro. Here, we describe HP1γ protein localisation in matured (MII) bovine oocytes and IVF preimplantation embryos at defined developmental stages. HP1γ is expressed in post-compaction embryos in a highly lineage-specific pattern. In embryonic stages preceding the maternal to embryonic transition (MET), HP1γ protein was primarily cytoplasmic, whereas in 8–16-cell embryos (post MET), HP1γ was primarily nuclear. Lineage-specific patterns of HP1γ protein localisation become evident from compaction, being restricted to peripheral, extraembryonic cells at the morula and blastocyst stages (Days 7–9). Surprisingly, we detected HP1γ mRNA in both embryonic and extraembryonic cells in blastocysts by fluorescence in situ hybridisation. In trophectoderm cells, HP1γ protein was localised in specific patterns at the mitotic and interphase stages of the cell cycle. These results demonstrate lineage- and cell cycle-specific patterns of HP1γ protein localisation in the post-compaction, preimplantation bovine embryo and raise interesting questions about the role of HP1γ in early embryo development.
Additional keywords: blastocyst, cell cycle, chromatin, HP1γ.
Acknowledgements
The authors thank Cathryn Hogarth (Loveland laboratory, Monash Institute of Medical Research) for advice and reagents for western blots. The authors gratefully acknowledge Stephen Firth (Monash Microimaging, Monash University) for training and technical advice regarding confocal microscopy, and Prince Henry’s Institute for Medical Research for the use of their confocal microscope. This project was funded by the Monash University Strategic Grant Scheme 2006 (CPG046) and supported by the Australian Research Council (no. 348239) and Victorian Government’s Operational Infrastructure Support Program.
Adjaye, J. , Huntriss, J. , Herwig, R. , BenKahla, A. , and Brink, T. C. , et al. (2005). Primary differentiation in the human blastocyst: comparative molecular portraits of inner cell mass and trophectoderm cells. Stem Cells 23, 1514–1525.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
Smallwood, A. , Esteve, P. O. , Pradhan, S. , and Carey, M. (2007). Functional cooperation between HP1 and DNMT1 mediates gene silencing. Genes Dev. 21, 1169–1178.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
Takanashi, M. , Oikawa, K. , Fujita, K. , Kudo, M. , Kinoshita, M. , and Kuroda, M. (2009). Heterochromatin protein 1γ epigenetically regulates cell differentiation and exhibits potential as a therapeutic target for various types of cancers. Am. J. Pathol. 174, 309–316.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
Telford, N. A. , Watson, A. J. , and Shultz, G. A. (1990). Transition from maternal to embryonic control in early mammalian development: a comparison of several species. Mol. Reprod. Dev. 26, 90–100.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed |
Tervit, H. R. , Whittingham, D. G. , and Rowson, L. E. (1972). Successful culture in vitro of sheep and cattle ova. J. Reprod. Fertil. 30, 493–497.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
Torres-Padilla, M. E. , Parfitt, D. E. , Kouzarides, T. , and Zernicka-Goetz, M. (2007). Histone arginine methylation regulates pluripotency in the early mouse embryo. Nature 445, 214–218.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
Vakoc, C. R. , Mandat, S. A. , Olenchock, B. A. , and Blobel, G. A. (2005). Histone H3 lysine 9 methylation and HP1gamma are associated with transcription elongation through mammalian chromatin. Mol. Cell 19, 381–391.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
Vandaele, L. , Mateusen, B. , Maes, D. G. , de Kruif, A. , and Van Soom, A. (2007). Temporal detection of caspase-3 and -7 in bovine in vitro produced embryos of different developmental capacity. Reproduction 133, 709–718.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
Zeng, F. , Baldwin, D. A. , and Schultz, R. M. (2004). Transcript profiling during preimplantation mouse development. Dev. Biol. 272, 483–496.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
Ziomek, C. A. , and Johnson, M. H. (1980). Cell surface interaction induces polarization of mouse 8-cell blastomeres at compaction. Cell 21, 935–942.
| Crossref | GoogleScholarGoogle Scholar | PubMed | CAS |
