Transcription factor Spi-B (SPIB)

Sequence specific transcriptional activator which binds to the PU-box, a purine-rich DNA sequence (5'-GAGGAA-3') that can act as a lymphoid-specific enhancer. Promotes development of plasmacytoid dendritic cells (pDCs), also called type 2 DC precursors (pre-DC2) or natural interferon (IFN)-producing cells.

These cells have the capacity to produce large quantities of interferon and prevent viral replication. May be necessary for B-cell receptor (BCR) signaling, which is vital for normal B-cell development and antigenic stimulation.