Spleen Focus Forming Virus Proviral Integration Oncogene (SPI1)

SPI1 encodes an ETS-domain transcription factor that activates gene expression during myeloid and B-lymphoid cell development. The nuclear protein binds to a purine-rich sequence known as the PU-box found near the promoters of target genes, and regulates their expression in coordination with other transcription factors and cofactors. The protein can also regulate alternative splicing of target genes. Multiple transcript variants encoding different isoforms have been found for this gene.The genomic locus was called Spi1, for SFFV proviral integration. Rearrangements due to SFFV integration were found in 95% of the erythroid tumors studied. A 4.0-kb mRNA was detected in rearranged tumors. The evolutionary conservation of the SPI1 locus was examined in cellular DNAs from various vertebrate species.