BTB And CNC Homology 1, Basic Leucine Zipper Transcription Factor 2 (BACH2)

The deduced 841-amino acid protein is 89.5% identical to mouse Bach2, with 97% identity shared in the BTB and bZIP functional domains and 94% identity shared in the serine-rich region. Northern blot analysis revealed expression of an approximately 11.0-kb BACH2 transcript restricted to thymus, spleen, and leukocytes; low levels were also detected in small intestine and brain.

Bach1 and Bach2 functioned as transcription repressors in transfection assays using fibroblast cells, but they functioned as a transcriptional activator and repressor, respectively, in cultured erythroid cells. Therefore, the authors suggested that the Bach proteins play important roles in coordinating transcription activation and repression by MafK.