Decreased rate of fatty acid synthesis in brown adipose tissue of hypothalamic obese rats

Intranuclear coinjection of the late SV40 KpnI/BclI DNA fragment and the early promotor/enhancer HpaII/BglI DNA segment into permissive monkey and non-permissive mouse cells allows late SV40 gene expression without T-antigen synthesis and DNA replication. These conditions were chosen to analyse the effect of DNA methylation on V-antigen synthesis detached from the process of DNA replication. We found that in vitro methylation of a single cytosine nucleotide proximal to the major late mRNA cap site by the HpaII methylase does not block capsid protein synthesis. This result is in contrast to reported data obtained in Xenopus laevis oocyte injection experiments (1982) Proc. Natl. Acad. Sci. USA 79, 5142-5146].