Nucleotide and deduced amino acid sequence of an actin cDNA clone from Plasmodium falciparum.

A full length cDNA clone (XZPfac) coding for actin of Plasmodium falciparum (strain FCB1) was isolated from a X-ZAP cDNA library by hybridization with synthetic oligonucleotides. The cDNA was synthesized from poly(A) mRNA of the asexual blood-stage (merozoite) of the parasite. A comparison of our sequence data with the actin sequence of isolate NF54, Amsterdam Airport strain (1) reveals several differences on the nucleotide level, most of which are located within the 5' nontranscribed region. Isolate NF54 contains an AT insertion at position 132 and an additional A at position 170 compared to XZPfac. Further, the nucleotides at positions 71 and 104 are deleted and the bases at positions 188/189 differ. Within the coding region, base alterations at position 349/350 and 1264 result in amino acid changes from a V to a D and a T to an I, respectively. The base alteration at position 1385 does not affect the amino acid sequence. A remarkable feature of the actin sequence in XZPfac is a stretch of 45 T nucleotides at the 5' end.