Molecular cloning and characterization of a cDNA for the highly conserved HMG-like protein (Pf16) gene of Plasmodium falciparum.

A cDNA clone (PfHB3-2-4) of 1538 bp corresponding to the highly conserved HMG-like protein (Pf16) was isolated. However, northern analysis suggests that the mRNA is about 2.2 to 2.3 kb. Analysis by RT-PCR indicated that the 0.6 to 0.7 kb sequence missing in the cDNA maps to the 3' end, suggesting that the cDNA is terminated within the 26 adenosine residues that are in the middle of the Pf16 sequence. The most unique feature about this cDNA is the presence of two open reading frames (ORF), one from nucleotides 91 to 927 and the other starting from 1421. The second ORF corresponds to Pf16. Expression of the cDNA clones in Escherichia coli and translation in rabbit reticulocytes of RNA transcribed from the T7 promoter of the cDNA clones revealed that only the 3' end Pf16 is translated from this mRNA. Further experiments with antisense oligonucleotides specific for Pf16 indicated that the Pf16 protein serves an important function in the life cycle of the parasite.