Effects of the TLR4 transgene on reproductive traits and DNA methylation pattern of oocytes in ewes

Abstract

This study was conducted to systematically assess the reproductive performance of transgenic TLR4 ewes. In the TLR4 transgenic founders (F₀) and their positive offspring (F₁), hematological and reproductive parameters and the global DNA methylation level in oocytes at various stages were analyzed. The values of the physiological and biochemical parameters determined from the blood samples did not differ significantly between the transgenic and wild-type ewes. Moreover, the transgenic ewes showed reproductive traits similar to the wild-type ewes. These traits included characteristics of puberty, the estrus cycle, estrus duration, gestation, the pregnancy rate and the superovulation response. Additionally, no significant differences were found between transgenic and wild-type ewes in the DNA methylation level of the oocytes at various stages. In summary, the preliminary evidence presented in this paper demonstrates that the presence of the TLR4 transgene did not affect the reproductive performance in sheep.

Keywords

TLR4 transgenic ewe / safety assessment / reproductive trait / oocyte / DNA methylation

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Acknowledgements

This study was supported by key special projects for breeding new varieties of genetically engineered organisms in China (2011ZX08011-004). We thank Dr. Guangbin Zhou (Sichuan Agricultural University, China) and Nature Publishing Group Language Editing (NPGLE) for proofreading the manuscript.

Compliance with ethics guidelines

Yi Fang, Xiangwei Fu, Junjie Li, Ming Du, Baoyu Jia, Jinlong Zhang, Xiaosheng Zhang and Shien Zhu declare that they have no conflict of interest or financial conflicts to disclose.

All applicable institutional and national guidelines for the care and use of animals were followed.

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag Berlin Heidelberg