Characterisation of the growth and differentiation in vivo and in vitro-ofbloodstream-form Trypanosoma brucei strain TREU 927

Trypanosoma brucei TREU 927/4 has been chosen as the reference strain targe ted for complete sequencing of the genome of the African trypanosome. This line is pleomorphic in mammalian hosts and is fly transmissible: however it is relatively unstable with respect to variable surface glycoprotein (VSG) expression. Therefore, we subjected TREU 927/4 to 27 rapid syringe passage s through mice, and derived a cloned line which expressed Glasgow Universit y Trypanozoon antigen type (GUTat) 10.1 with relative stability. This line also retained pleomorphism in the bloodstream, being able to generate homog eneous populations of stumpy forms in mice. Furthermore. these parasites re main able to transform to procyclic forms synchronously in vitro and can co mplete their life cycle in tsetse flies. The passaged cell line was also ad apted to in vitro bloodstream-form culture and transfected with a construct encoding the tetracycline repressor (TETR) protein. The resulting TETR sub line no longer expressed the GUTat 10.1 VSG but remained able to generate u niform populations of stumpy form cells in mice immunocompromised with cycl ophosphamide. They could also differentiate to procyclic forms synchronousl y in vitro. The generated lines and analyses of their growth and differenti ation will provide a basic resource for the analysis and interpretation of gene function in the T. brucei genome reference strain. (C) 2001 Elsevier S cience B.V. All rights reserved.