Cloning and sequence of a β‐tubulin cDNA from Pneumocystis carinii: possible implications for drug therapy

This work describes the isolation and characterization of a full‐length cDNA clone encoding β‐tubulin from the pathogen Pneumocystis carinii, P. carinii contains a single gene encoding β‐tubulin. The complete sequence of this cDNA has been determined and its inferred amino acid sequence compared with the β‐tubulins from other organisms. This analysis augments the data indicating that P. carinii should be classified as a fungal organism. Further comparisons between the P. cariniiβ‐tubulin and those of fungal β‐tubulins resistant to benomyl, a β‐tubulin‐binding drug, indicate a difference which may be exploited in the development of a new drug therapy for P. carinii pneumonitis. These results suggest that, theoretically, a drug presently administered for treatment of nematode worm infections may be an effective agent against P. carinii, without being toxic to the mammalian host. This possibility is currently being investigated.