Figure 7.
A decrease in Foxo1 protein in primary immature B cells interferes with Rag1 and Rag2 transcript induction in response to BCR crosslinking. Quantitative RT-PCR analysis of Rag1 or Rag2 transcripts in cultured immature B cells from Rag1-GFP-heterozygous mice, infected with retrovirus encoding shRNA targeting either GFP or Foxo1, then collected 4 dlater, labeled with the appropriate antibodies and sorted by flow cytometry to isolate B220loIgM+ immature B cells bearing the retroviral marker protein. Sorted immature B cells were then left untreated or incubated for 12-15 h with anti-IgM before being collected for RNA isolation. Rag1 and Rag2 transcripts quantified by real-time PCR were normalized to Hprt1 transcripts, with the lowest value set as 1. Numbers above bars indicate the ‘fold difference’ (×) in transcript abundance between control cells and cells treated with anti-IgM. Data are representative of two independent experiments.