Gene trapping of two novel genes, Hzf and Hhl, expressed in hematopoietic cells

Using an expression gene trapping strategy, we have identified and characte rized two novel hematopoietic genes, Hzf and Hhl. Embryonic stem (ES) cells containing a gene trap vector insertion were cultured on OP9 stromal cells to induce hematopoietic differentiation and screened for lacZ reporter gen e expression. Two ES clones displaying lacZ expression within hematopoietic cells in vitro were used to generate mice containing the gene trap integra tions. Paralleling this in vitro expression pattern, both Hzf and Hhl were expressed in a tissue-specific manner during hematopoietic development in v ivo. Hzf encodes a novel protein containing three C2H2-type zinc fingers pr edominantly expressed in megakaryocytes and CFU-GEMM. Hhl encodes a novel p rotein containing a putative phosphotyrosine binding (PTB) domain expressed in megakaryocytes, CFU-GEMM and BFU-E. These results demonstrate the utili ty of expression trapping to identify novel hematopoietic genes. Future stu dies of Hzf and Hhl should provide valuable information on the role these g enes pray during megakaryocytopoiesis. (C) 2000 Elsevier Science ireland Lt d. All rights reserved.