African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12193

Full Length Research Paper

Limited variation of the 5’cis-control region of the transmission blocking vaccine candidate Pfs25 amid great genetic diversity of Plasmodium falciparum in Cameroon

Wilfred Fon Mbacham1*, Patrice Nsangou Mimche1, Palmer Masumbe Netongo1, Evehe Bebandoue Marie-Solange1, Akindeh Nji1, Immaculate Amunom1, Johanna Daily2, Valerie Makoge1, Kayla Laserson2, Songmbe Michael Yong3, Nicoline Lomah3, Peter Enyong4, Vincent P. Titanji3 and Dyann F. Wirth2
  1The Biotechnology Center, University of Yaounde I, Cameroon. 2Department of Immunology and Infectious Diseases, Harvard School of Public Health, U.S.A. 3Biotechnology Unit, University of Buea, Cameroon. 4Center for Medical and Medicinal Plant Research, Ministry of Scientific Research, Kumba, SWP, Cameroon.
Email: [email protected]

  •  Accepted: 06 February 2008
  •  Published: 04 March 2008

Abstract

 

Genetic recombination during sexual reproduction within Plasmodium sp.contributes to parasite diversity and altered gene expression of certain surface markers. The pfs25 gene involved in the upset of gametocytogenesis is a candidate antigen in transmission blocking vaccine. This study investigated the polymorphism of Pfs25 within its 5’cis-control region in field isolates from different ecotypes in Cameroon.  Symptomatic patients and asymptomatic healthy school children with a positive smear and from different ecozones were included. Parasite DNA was extracted and polymorphisms within pfs25cg2-ω, msp-1, msp-2 andglurp genes were investigated by PCR-RFLP and DNA sequencing.  Putative control elements of the 5’cis control regions of Pfs25 were identified by PCGENE software and enzymes were selected whose sequences produced or abolished restriction sites by mutations. Malaria infection was mainly caused by Plasmodium falciparum with sporadic occurrence of Plasmodium malariae and Plasmodium ovale. Analysis of the Pfs25 5’ cis-control region identified only one polymorphism (0.002%) that abolished an RsaI restriction site as part of the sequence TTTCTGTAC, located 40 bp downstream of the promoter and found at – 478 bp of the ATG. Analysis of the 5’ cis-control sequence of Pfs25 revealed minimal variation of the promoter region amid great zonal differences in parasite population. Altitudinal differences in parasite populations were not easily discernable.

 

Key words: Plasmodium falciparum, Pfs25, cis-control elements, genetic polymorphism.