We used microarrays to establish whether EBF1 and Pax5 repress similar or unique genes. We found that EBF1 uniquely represses the expression of the T-lineage transcription factor Gata3. Ebf1-/- pre-pro-B cells were transduced with either control MigR1, MigY-EBF1 or MigR-Pax5 viruses. 24 hours later, RNA was isolated and processed for Affymetrix microarray analysis. Cells expressing EBF1, Pax5, or neither were sorted and processed. Scale represents log2 value of normalized signal level.