Complex sentence: SHP-1 gene has two promoters-P-1, active in epithelial cells, and P-2, active in hemopoietic cells.
Split into simpler sentences: SHP-1 gene has two promoters. The SHP-1 P-1 promoter is expressed in epithelial cells and the SHP-1 P-2 promotor expresses SHP-1 in hemopoietic cells.