Identification of adjacent binding sites for the YY1 and E4BP4 transcription factors in the ovine PrP (Prion) gene promoter.

The PrP gene encodes the cellular isoform of the prion protein (PrP(c)) which has been shown to be crucial to the development of transmissible spongiform encephalopathies (TSEs). PrP knock-out mice, which do not express endogenous PrP(c), exhibit resistance to TSE disease. The regulation of PrP gene expression represents, therefore, a crucial factor in the development of TSEs.

Use of BRL-conditioned medium in combination with feeder layers to isolate a diploid embryonal stem cell line.

The derivation of a karyotypically normal embryonal stem (ES) cell line, E14, from inner cell masses (ICMs) isolated by immunosurgery from 129/Ola late mouse blastocysts is described. Disaggregated ICMs were cultured on mitotically-arrested fibroblast feeder layers in droplets of medium conditioned with Buffalo rat liver (BRL) cells under oil. BRL-conditioned medium inhibits the differentiation of established embryonal carcinoma (EC) and ES cell lines which can be maintained indefinitely in the complete absence of feeder cells (Smith and Hooper 1987).