SPI-C, a PU-box binding ETS protein expressed temporarily during B-cell development and in macrophages, contains an acidic transactivation domain located to the N-terminus.
Mice deficient for SPI-group ETS transcription factors PU.1 or SPI-B fail to generate lymphocytes or do not mount normal antibody mediated immune responses, respectively. PU.1 expression is restricted to B-, T-lymphocytes and macrophages, while SPI-B is expressed in B- and T-lymphocytes. SPI-C is an ETS transcription factor closely related to PU.1 and SPI-B, and expressed temporarily during B-cell
