However, the intracellular expression of hIFN-a did not significantly promote the development of transgenic SCNT embryos. This is the first report of the expression of intracelluar IFN-a in embryos. Whether intracelluar IFN-a can elicit the same biological response in MR 16728 hydrochloride embryos as extracellular IFN-a needs to be further investigated. It has been reported that intrauterine application of hIFN-a can change bovine endometrial gene expression in early pregnancy, suggesting that hIFN-a may affect embryo implantation and pregnancy. However, the pregnancy rate of the hIFN-a transgenic SCNT embryos was not significantly different from that associated with the control embryos in this study. One explanation for this might be that the non-secreted hIFN-a could not elicit a response from the endometrial cells when transgenic SCNT embryos were implanted into surrogate cows. The two live-born hIFN-a transgenic SCNT calves in this study had normal external anatomy and organ development. These results indicate that PG 01037 dihydrochloride constitutive expression of intracelluar IFN-a does not have obvious negative effects on the early-stage development of transgenic SCNT calves. IFN-a can influence the proliferation, differentiation, and function of various types of cells in the immune system and thus influence lympho-hematopoiesis. However, it has been proposed that this effect only takes place under conditions of trauma or inflammation. These factors could explain why expression of hIFN-a did not have obvious adverse effects on transgenic calves in our study. This is supported by a report in which transgenic mice expressing IFN-b displayed similar behavior, external anatomy, life span, and female fertility as wild type mice, although male transgenic mice displayed reduced fertility. The idiopathic infertilities may be caused by IFNs in the extracellular fluid, which affect the interplay between germ cells and Sertoli cells. It has also been shown that the level of IFN-a in the seminal plasma may be related to sperm production. Intracellular expression of hIFNa did not result in a high level of IFN-a in the seminal plasma in our study. However, the fertility and the viral resistance of the transgenic calves need to be further determined. The calf is now 17 months old and continued GFP expression has been shown by immunofluorescence in an ear biopsy and in fibroblasts derived from the animal. In conclusion, we constructed a vector with a hIFN-a gene cassette.