Analysis of Fv-1 restriction in two murine embryonal carcinoma cell lines and a series of differentiated derivatives.
We have used antibiotic-resistant retrovirus vectors rescued by Fv-1-sensitive murine leukaemia viruses (MuLV) to examine the Fv-1 phenotype of two undifferentiated embryonal carcinoma (EC) cell lines derived from teratocarcinomas of mouse strain 129. In addition, a set of EC cell-derived differentiated cell lines was analysed. Restriction of both B-tropic and endogenous N-tropic virus is characteristic of the Nr-type restriction reported in mouse strain 129. However, results indicate that Fv-1 restriction is not expressed in the PCC4.aza1R EC cell line. In contrast, the F9 EC cell line showed a strong restriction of the B-tropic pseudotyped vector but failed to restrict endogenous N-tropic pseudotypes. The Fv-1 gene thus seems to be differentially expressed in two EC cell lines derived from the same mouse strain. Furthermore, the selective restriction of B-tropic but not endogenous N-tropic MuLV in F9 cells suggests that these activities function independently of each other. Analysis of PCC4.aza1R-derived differentiated cell lines revealed that three fibroblast cell lines derived by retinoic acid-induced differentiation were also phenotypically silent for Fv-1. However, a pre-adipocyte line established following simultaneous exposure to retinoic acid and 5-azacytidine showed strong restriction of both B-tropic and endogenous N-tropic MuLV. Although additional data suggest that there is no correlation between the differentiated pre-adipocyte phenotype and Fv-1 expression, our results nonetheless show that Nr restriction can be observed in some derivatives of PCC4.aza1R cells, presumably by activating expression of the Fv-1 gene.
Heitman
C K
CK
Cellular and Genetic Toxicology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.
Innes
C L
CL
Jetten
A M
AM
Boone
L R
LR
D000818:Animals; D054278:Embryonal Carcinoma Stem Cells; D015972:Gene Expression Regulation, Neoplastic; D005796:Genes; D005822:Genetic Vectors; D009052:Leukemia Virus, Murine / Q000502:physiology*; D051379:Mice; D014411:Neoplastic Stem Cells / Q000382:microbiology*; D010641:Phenotype; D014407:Tumor Cells, Cultured; D014779:Virus Replication / Q000235:genetics