Spi-C Transcription Factor (SPIC)

SPIC is highly expressed in red pulp macrophages, but not monocytes, dendritic cells, or other tissue macrophages. Spic-null mice have a cell-autonomous defect in the development of red pulp macrophages that is corrected by retroviral Spic expression in bone marrow cells, but have normal monocyte and other macrophage subsets. Spic-null mice show normal trapping of red blood cells in the spleen but fail to phagocytose these red blood cells efficiently, and develop an iron overload localized selectively to splenic red pulp.Mouse and human SPIC share 65% amino acid identity. RNA dot blot analysis detected high SPIC expression in fetal spleen, moderate expression in adult lymph node and spleen, and low expression in adult brain and bone marrow and fetal liver.