Sp1 is an important transcriptional regulation factor for forkhead box N1 in pig.

The transcription factor forkhead box N1 (Foxn1) plays an important role in the development and function of thymic epithelial cells (TECs) in vertebrates. However, the transcriptional regulation of Foxn1 is still unknown. A series of dual luciferase report vectors were constructed and their relative activities were also detected. The 5'-untranslated regions contains two cis-acting elements, Sp1 and GATA-1, as well as trans-acting elements between positions -332 to -438. Nevertheless, the relative activities of Foxn1 promoter were significantly increased in PK15 cells only when the Sp1 was overexpressed, suggesting that the Sp1 was the most important sequence for Foxn1 transcription activation in the pig. Regrettably, the exact trans-acting elements were not found.