Identification of three proteins that associate in vitro with the Leishmania (Leishmania) amazonensis G-rich telomeric strand. |
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| Authors: | Maribel F Fernández Rafael R Castellari Fábio F Conte Fábio C Gozzo Ad?o A Sabino Hildete Pinheiro José C Novello Marcos N Eberlin Maria I N Cano |
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| Institution: | Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Brazil. |
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| Abstract: | The chromosomal ends of Leishmania (Leishmania) amazonensis contain conserved 5'-TTAGGG-3' telomeric repeats. Protein complexes that associate in vitro with these DNA sequences, Leishmania amazonensis G-strand telomeric protein (LaGT1-3), were identified and characterized by electrophoretic mobility shift assays and UV cross-linking using protein fractions purified from S100 and nuclear extracts. The three complexes did not form (a) with double-stranded DNA and the C-rich telomeric strand, (b) in competition assays using specific telomeric DNA oligonucleotides, or (c) after pretreatment with proteinase K. LaGT1 was the most specific and did not bind a Tetrahymena telomeric sequence. All three LaGTs associated with an RNA sequence cognate to the telomeric G-rich strand and a complex similar to LaGT1 is formed with a double-stranded DNA bearing a 3' G-overhang tail. The protein components of LaGT2 and LaGT3 were purified by affinity chromatography and identified, after renaturation, as approximately 35 and approximately 52 kDa bands, respectively. The
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