BOVINE STEM-CELL FACTOR - PRODUCTION OF A BIOLOGICALLY-ACTIVE PROTEINAND MESSENGER-RNA ANALYSIS IN CATTLE INFECTED WITH TRYPANOSOMA-CONGOLENSE

The cDNA coding for the soluble form of bovine stem cell factor (boSCF (Ala165)) was cloned and recombinant protein was produced in bacteria as a histidine tagged-protein. The protein was purified from the inclu sion bodies in one step by metal chelation chromatography under denatu ring conditions. Recombinant bovine SCF was shown to act synergistical ly with interleukin 3 (IL-3) and erythropoietin (EPO) in stimulating t he growth of bone marrow progenitor cells such as colony forming units -granulocyte macrophage (CFU-GM) and burst forming units-erythroid (BF U-E). Analysis of SCF mRNA expression by reverse transcription-polymer ase chain reaction (RT-PCR) revealed that the transcripts were detecta ble in bone marrow, lymph node and spleen of cattle, and that the leve l of transcription was upregulated in lymph nodes of cattle infected w ith Trypanosoma congolense. Two isoforms of SCF mRNA were amplified by RT-PCR. The availability of recombinant bovine SCF provides a valuabl e tool for studying the role of SCF in the development, growth and dif ferentiation of bovine hematopoietic cells. (C) 1997 Elsevier Science B.V.