The GFI1 Gene Family: Evolution, Structure, and Its Role in Immune Responses

The immune system’s evolution is crucial for its role in fighting pathogens and involvement in autoimmune and neurodegenerative diseases. The GFI1 gene family controls the function of immune cells, including neutrophils in the innate immune system and CD4+ T cells in the adaptive immune system. GFI1 consists of two members, GFI1A and GFI1B. GFI1A is vital for myeloid and lymphoid differentiation, while GFI1B is crucial for generating red blood cells and platelets. Both genes share a repressor SNAG protein and C2H2 zinc finger domains, though the peptide sequences between these domains remain uncharacterized. Using a comprehensive phylogenetic approach, we traced the evolutionary history of the GFI1 gene family, revealing its early presence in invertebrates. Two rounds of genome duplication led to GFI1A and GFI1B. Despite positive selection, the family retained structural conservation. We identified new motifs in the less-characterized middle regions, such as the SPOP-binding motif in GFI1A, potentially regulating cytokine production, and the FEDFW motif, possibly involved in neutrophil recruitment. These motifs are unique to GFI1A in higher vertebrates. In GFI1B, we discovered a unique EPLRP motif, a Separase cleavage site linked to sister chromatid separation. Our results indicate that GFI1 has evolved new functions to adapt to the complexity of the vertebrate immune system. This highlights the evolutionary significance of GFI1 in immune responses and suggests potential therapeutic applications, especially in diseases related to immune function.