Files in this Data Supplement:

• Supplemental file 1 - Supplementary figure legends
  MS Word document, 50 K.
• Supplemental file 2 - Supplementary methods
  MS Word document, 40 K.
• Supplemental file 3 - Fig. S1 (Construction of the Prdm1:TVB-mRFP transgene by recA-mediated BAC modification.)
  Zipped EPS file, 1.2 MB.
• Supplemental file 4 - Fig. S2 (BAC modification by homologous recombination in E. coli.)
  Zipped EPS file, 4 MB.
• Supplemental file 5 - Fig. S3 (In situ detection of the TVB-mRFP receptor in thymus and gut tissue from Prdm1:TVB-mRFP transgenic animals.)
  Zipped EPS file, 8 MB.
• Supplemental file 6 - Fig. S4 (Expression of TVB is required for transduction by an ALV vector bearing a subgroup B envelope.)
  Zipped EPS file, 17.5 MB.