Molecular Characterization and Sequencing of a Gene Encoding Mannose Binding Protein in an Iranian Isolate of Acanthamoeba castellanii as a Major Agent of Acanthamoeba keratitis

Abstract

Background: Acanthamoeba castellanii is the important cause of amoebic keratitis in Iran. The key molecule in pathogene­sis of Acanthamoeba keratitis is Mannose Binding Protein (MBP) led to adhesion of amoeba to corneal epithelium. Subse­quent to adhesion other cytopathic effects occur. The goal of this study was to identify the molecular characterization of a gene encoding MBP in an Iranian isolate of A.castellanii in order to pave the way for further investigations such as new therapeu­tic advances or immunization.

Methods: A.castellanii was cultured on non nutrient agar. Extraction of DNA was performed by phenol-chloroform method. After designing a pair of primer for the gene encoding MBP, PCR analysis was performed. Finally, the PCR prod­uct has been sequenced and the result submitted to the gene data banks.

Results: An MBP gene of 1081 nucleotides was sequenced. This fragment contained three introns and encodes a protein with 194 amino acids. Homology search by Blast program showed a significant homology with the MBP gene in gene data banks (96%). Besides, the identity of amino acids with the other MBPs in gene data banks was about 86%.

Conclusion: We isolated and sequenced a gene fragment encoding MBP in an Iranian isolate of A.castellanii. Molecular characteri­zation of this important gene is the first step in pursuing researches such as developing better therapeutic agents, im­mu­nization of population at risk or even developing a diagnostic tool by PCR techniques.