Survival of Trypanosoma brucei in the Tsetse Fly Is Enhanced by the Expression of Specific Forms of Procyclin

摘要: African trypanosomes are not passively transmitted, but they undergo several rounds of differentiation and proliferation within their intermediate host, the tsetse fly. At each stage, survival successful replication parasites improve chances continuing life cycle, little is known about specific molecules that contribute to these processes. Procyclins major surface glycoproteins insect forms Trypanosoma brucei. Six genes encode proteins with extensive glutamic acid–proline dipeptide repeats (EP in single-letter amino acid code), two an internal pentapeptide repeat (GPEET). To study function procyclins, we have generated mutants no EP only one copy GPEET. This last gene could be replaced by deleted once a second GPEET was introduced into another locus. The knockouts morphologically indistinguishable from parental strain, ability establish heavy infection midgut severely compromised; this phenotype can reversed reintroduction single, highly expressed gene. These results suggest types procyclin different roles, form, while required culture, important for