Reproduction Abstracts

Coxsackie virus and adenovirus receptor, CXADR (CAR) is a member of the tight junction protein (TJP also known as JAM) family of adhesion receptor and located on a cytoplasmic membrane surface of intercellular tight junctions. CXADR are reported to be expressed during preimplantation in human embryos, but its function in early embryo development was not investigated. In the present study we determine temporal and spatial expression patterns of CXADR in porcine embryos and investigated the biological function in blastocyst formation. Porcine CXADR was detected in all stages of preimplantation, and highly up-regulated from eight-cell stage onward, particularly CXADR protein was translocalised into intercellular boundary at morula and blastocyst. To deplete both maternally and zygotically expressed CXADR, an RNAi approach was employed. Microinjection of CXADR dsRNA resulted in a ~90% reduction of mRNA and complete loss of protein. In CXADR knockdown (KD) embryos, blastocyst development was significantly lower (11.26% vs 38.32%) and most embryos were arrested prior to morula. We also examined genes required for and involved in tight junction biogenesis using qRT-PCR. Expression of tight junction associated genes such as ZO-1, and OCLN were decreased but TFAP2C, OCT4, and PARD6B were not changed. In conclusion, our results suggested that CXADR plays a critical role in blastocyst formation in terms of establishment of tight junction complex.

This work was supported by ‘Next-Generation BioGreen21 Program’ (PJ 011213), Rural Development Administration (RDA), Republic of Korea.