Cloning and molecular characterization of a gene encoding a Cryptosporidium parvum putative 20S proteasome beta1-type subunit.

A DNA sequence composed of 1281 nucleotides (nt) consisting of a single open reading frame (ORF) encoding a putative 20S proteasome beta1-type subunit was isolated from clones derived from genomic libraries constructed from the KSU-1 isolate of Cryptosporidium parvum. Southern blot analysis suggested that the sequenced DNA exists in the C. parvum genome as a single copy; transcription was verified through reverse transcription-polymerase chain reaction (RT-PCR) performed on total RNA isolated from C. parvum sporozoites. The predicted protein consists of 210 amino acids (aa), contains characteristic amino acids common to all proteasomal subunits, and shares stronger similarity to the beta1-type subunit of yeast than to other types of beta-subunits.