Examination of a virulence mutant uncovers the ribosome biogenesis regulatory protein of Toxoplasma

J Parasitol. 2011 Jul 7. [Epub ahead of print]

Examination of a virulence mutant uncovers the ribosome biogenesis regulatory protein of Toxoplasma gondii

Milligan-Myhre KC, Rooney PJ, Knoll LJ

Sourcea Department of Molecular Biology, University of Oregon, Eugene, Oregon, 97403.

Abstract
Abstract Several insertional mutants identified in a screen for Toxoplasma gondii that were defective in establishing a chronic infection had a common site of plasmid insertion. This insertion site was determined to be 43 bp upstream of the transcription initiation site of a gene whose predicted product has homology to ribosome biogenesis regulatory protein Rrs1p, an essential protein required for ribosome biogenesis in Saccharomyces cerevisiae. Northern blot analysis of this locus, termed TgRRS1, showed that in the C3 mutant, the full-length transcript is downregulated and at least one new smaller transcript is present. Restoration of the intact predicted promoter and locus to TgRRS1 insertional mutant strain C3 did not restore brain cyst formation to the levels of the parent strain. Epitope-tagged TgRRS1 was found to localize to the parasite nucleolus, in an area corresponding to the granular component region. TgRRS1 can serve as a marker for the subnucleolar granular component region of T. gondii.

PMID:21736491[PubMed - as supplied by publisher]