FIG. 6.
Multiple pregnancies up-regulate expression of Emv1. RNA was isolated from the spleens of retired breeder BALB/cJ females and males and of virgin BALB/cJ females. Twenty micrograms of RNA was subjected to Northern blot analysis with ecotropic virus-specific (A) and xenotropic-polytropic-MCF virus-specific (B) probes. Full-genome (8.3-kb) and subgenomic (2.3-kb) viral transcripts are shown.