Adipogenesis in mouse 3T3L1 cells: the effects of Rtl1 over-expression.

Rtl1 and Dlk1 are two genes in an imprinted gene cluster on mouse chromosome 12. Rtl1 is a paternally expressed gene encoding a retrotransposon-like protein, but as yet, there is no evidence that a protein is produced by this gene although a transcript is produced. Dlk1 is also paternally expressed and it encodes a plasma membrane-bound protein known to act as a negative regulator of adipogenesis. Genes at other imprinted loci often show coordinate expression and may interact at a functional level. We tested the hypothesis that Dlk1 and Rtl1 are functionally related. Rtl1 and Dlk1 mRNA expression patterns show similar time courses of down-regulation during induced adipogenesis of 3T3L1 cells. Despite the coordinate down-regulation of Dlk1 and Rtl1 mRNA levels, Rtl1 over-expression did not affect the time course of adipogenesis or Dlk1 expression. It is concluded that these two genes are neither directly nor indirectly functionally related.