UBC Theses and Dissertations
Sequence analysis of the Leishmania mexicana amastigote specific gene a600 Zhao, Min
Various species of the genus Leishmania infect millions of people, causing a wide spectrum of diseases collectively termed as leishmaniases, with a wide distribution in tropical and sub-tropical areas. The parasite alternates between the promastigote form predominately in the insect vector and the intracellular amastigote form in the vertebrate host, including human. Accumulating evidences suggest that developmental stagespecific genes are responsible for morphological, physiological and biochemical differences between the two life stages. Particularly, the amastigote-specific genes are of great importance in term of the host-parasite relationship. The a600 gene, previously identified in our lab, is amastigote-specific in Leishmania mexicana. In the present study, the gene was sequenced using Nested Deletion. Sequence analysis indicated that the a600 gene encodes a novel 93-amino acid polypeptide. Predictions based on the amino acid sequence indicated that the putative polypeptide is likely a membrane protein as a transmembrane helix region is predicted. However, the putative polypeptide was neither detected in cell lysate nor in the medium of the promastigotes transfected with the Leishmania expression vector pLexSat containing coding region of a600 attached with the Flag sequence. Nevertheless Northern Blot showed the presence of the RNA transcribed from the insert, suggesting the involvement of post-translational regulation. Sequence variation was also observed at the 3'-untranslated region of the a600 gene, suggesting the a600 a multiple copy gene family. The approaches for further experiment were discussed.
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