International Journal of Animal Breeding and Genetics

International Journal of Animal Breeding and Genetics Vol. 8 (12), pp. 001-011, December, 2019. © International Scholars Journals

Full Length Research Paper

The African trypanosomes ADP-ribosylation factor 1 has species-specific motif signatures and is developmentally regulated

Alex Osanya1, 2*, Roger Pellé1, Francis Chuma1, Clive Wells3 and Noel B. Murphy4

1International Livestock Research Institute, P. O. Box 30709, Nairobi, Kenya.

2University of Nevada, Department of Biochemistry and Molecular Biology, Reno, Nevada, USA 89557.

3Medical College of Wisconsin, Microbiology and Molecular Genetics, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA.

4Department of Biology, Institute of Immunology, National University of Ireland, Maynooth, Ireland.

Accepted 16 May, 2019

Abstract

Small GTP-binding proteins of the ADP-ribosylation factor (Arf) family are essential for vesicle formation, intracellular and membrane trafficking and signal transduction. We have cloned and characterized the homologue of Arf1 from Trypanosoma b. brucei, Trypanosoma evansi, Trypanosoma congolense and Trypanosoma vivax. The African trypanosome Arf1 cDNA contains an open reading frame of 546 base pairs, corresponding to a 181 amino acid residue polypeptide. The protein carries conserved motifs in the GTP-binding domains for Arf1 proteins and a myristoylation site in addition to domains specific to trypanosomes. The TbArf1 gene generates a transcript of approximately 0.9 kb that is developmentally regulated. Recombinant TbArf1 expressed in Escherichia coli binds GTP. GDP and GTP were efficient competitors of [a32P]- GTP binding to the protein but not ATP or CTP. Polyclonal antibodies raised against the recombinant TbArf1 revealed a major protein band of about 21 kDa in T. b. brucei and T. congolense lysates and additional weaker binding to proteins of higher molecular weight in both lysates. The protein localizes in endosomal compartments between the nucleus and kinetoplast but in addition it also displays a flagellar localisation. The TbArf1 protein is detected in supernatant of in vitro cultivated parasites.

Key words: Recombinant expression, antibodies, secretion, endocytosis, differential gene expression, GTP-binding.