@article{sommer_jackson_simpson_collins_piedrahita_petters_2012, title={Transgenic Stra8-EYFP pigs: a model for developing male germ cell technologies}, volume={21}, ISSN={["0962-8819"]}, DOI={10.1007/s11248-011-9542-6}, abstractNote={The male germ line in mammals is composed of self-renewing cells, spermatogonia, the meiotic spermatocytes and spermiogenic spermatids. Identification of these cell stages in vitro has been problematic. Transgenic animals expressing a marker gene with a promoter specific to certain cell stages in the testis would be a useful approach to identifying these cells in a viable state. Towards this end, we have produced transgenic pigs expressing mitochondrial localized enhanced yellow fluorescent protein (EYFP-mito) under control of the germ cell specific Stimulated by Retinoic Acid 8 (Stra8) promoter. Stra8 has been shown to be expressed in pre-meiotic germ cells of mice. Twelve clones harboring the Stra8-EYFP-mito transgene were produced. Analysis by Western blot indicated that expression of the transgene was limited to testicular tissue in the transgenic pigs. Single cells and seminiferous tubules were cultured in vitro and subsequently examined with epifluorescent microscopy. Expression of EYFP was noted in cells cultured for up to 5 days. Both EYFP-mito and STRA8 antibodies were shown to bind and co-localize in seminiferous tubule cells in whole mounts and in histological sections. EYFP-mito in the transgenic pigs co-localized with the endogenous stem cell marker, NANOG. Expression of the Stra8-EYFP transgene in spermatogenic cells indicates that these pigs will be useful by providing labelled cells for use in such technologies such as germ cell transplantation and in vitro spermatogenic studies.}, number={2}, journal={TRANSGENIC RESEARCH}, author={Sommer, Jeffrey R. and Jackson, Lauren R. and Simpson, Sean G. and Collins, Edwin B. and Piedrahita, Jorge A. and Petters, Robert M.}, year={2012}, month={Apr}, pages={383–392} }
 @article{lim_piedrahita_jackson_ghashghaei_olby_2010, title={Development of a Model of Sacrocaudal Spinal Cord Injury in Cloned Yucatan MiniPigs for Cellular Transplantation Research}, volume={12}, ISSN={["2152-4998"]}, DOI={10.1089/cell.2010.0039}, abstractNote={Research into transplantation strategies to treat spinal cord injury (SCI) is frequently performed in rodents, but translation of results to clinical patients can be poor and a large mammalian model of severe SCI is needed. The pig has been considered an optimal model species in which to perform preclinical testing, and the Yucatan minipig can be cloned successfully utilizing somatic cell nuclear transfer (SCNT). However, induction of paralysis in pigs poses significant welfare and nursing challenges. The present study was conducted to determine whether Yucatan SCNT clones could be used to develop an SCI animal model for cellular transplantation research. First, we demonstrated that transection of the sacrocaudal spinal cord in Yucatan SCNT clones produces profound, quantifiable neurological deficits restricted to the tail. We then established that neurospheres could be isolated from brain tissue of green fluorescence protein (GFP) transfected SCNT clones. Finally, we confirmed survival of transplanted GFP-expressing neural stem cells in the SCI lesion and their differentiation into glial and neuronal lineages for up to 4 weeks without immunosuppression. We conclude that this model of sacrocaudal SCI in Yucatan SCNT clones represents a powerful research tool to investigate the effect of cellular transplantation on axonal regeneration and functional recovery.}, number={6}, journal={CELLULAR REPROGRAMMING}, author={Lim, Ji-Hey and Piedrahita, Jorge A. and Jackson, Lauren and Ghashghaei, Troy and Olby, Natasha J.}, year={2010}, month={Dec}, pages={689–697} }