A C-terminal deletion mutant of pokeweed antiviral protein inhibits programmed +1 ribosomal frameshifting and Ty1 retrotransposition without depurinating the sarcin/ricin loop of rRNA.
Pokeweed antiviral protein (PAP) is a ribosome-inactivating protein characterized by its ability to depurinate the sarcin/ricin (S/R) loop of the large rRNA of prokaryotic and eukaryotic ribosomes. Here, a series of PAP mutants were used to examine the relationship between depurination of the S/R loop and inhibition of +1 programmed ribosomal frameshifting (PRF) and to define PAP sequences critical for inhibition of +1 PRF and Ty1 retrotransposition in the yeast Saccharomyces cerevisiae. Using three different classes of mutants we present evidence that strong binding of a C-terminal PAP mutant (PAPc) to ribosomes is sufficient to inhibit +1 PRF and Ty1 retrotransposition in the absence of S/R loop depurination. PAPc did not affect the totivirus ScV-L-A and HIV-1-directed -1 PRF efficiencies or the ability of cells to maintain the M(1)-dependent killer phenotype, demonstrating the specificity of the effect of PAPc on +1 PRF.
Hudak
K A
KA
Biotechnology Center for Agriculture and the Environment and Department of Plant Pathology, Cook College, Rutgers University, New Brunswick, New Jersey, 08903-0231, USA.
Hammell
A B
AB
Yasenchak
J
J
Tumer
N E
NE
Dinman
J D
JD
D002460:Cell Line; D018965:Frameshifting, Ribosomal; D017353:Gene Deletion; D015497:HIV-1 / Q000502:physiology; D009699:N-Glycosyl Hydrolases; D009690:Nucleic Acid Conformation; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D011687:Purines / Q000378:metabolism; D012328:RNA Viruses / Q000502:physiology; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D018626:Retroelements; D054789:Ribosome Inactivating Proteins, Type 1; D012270:Ribosomes / Q000378:metabolism; D012276:Ricin / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism
D010940:Plant Proteins; D011687:Purines; D012335:RNA, Ribosomal; D018626:Retroelements; D054789:Ribosome Inactivating Proteins, Type 1; D012276:Ricin; D009699:N-Glycosyl Hydrolases; C024275:pokeweed antiviral protein