The ribosomal P-proteins of the medfly Ceratitis capitata form a heterogeneous stalk structure interacting with the endogenous P-proteins, in conditional P0-null strains of the yeast Saccharomyces cerevisiae.
The genes encoding the ribosomal P-proteins CcP0, CcP1 and CcP2 of Ceratitis capitata were expressed in the conditional P0-null strains W303dGP0 and D67dGP0 of Saccharomyces cerevisiae, the ribosomes of which contain either standard amounts or are totally deprived of the P1/P2 proteins, respectively. The presence of the CcP0 protein restored cell viability but reduced the growth rate. In the W303CcP0 strain, all four acidic yeast proteins were found on the ribosomes, but in notably less quantity, while a preferable binding of the YP1alpha/YP2betapair was established. In the absence of the endogenous P1/P2 proteins in the D67CcP0 strain, the complementation capacity of the CcP0 protein was considerably reduced. The simultaneous expression of the three medfly genes resulted in alterations of the stalk composition: both the CcP1 and CcP2 proteins were found on the particles substituting the YP1alphaand YP2alpha proteins, respectively, but their presence did not alter the growth rate, except in the case of the YP1alpha/betadefective strain, where a helping effect on the binding of the YP2alphaand YP2betaproteins on the ribo-somes was confirmed. Therefore, the medfly ribosomal P-proteins complement the yeast P-protein deficient strains forming an heterogeneous ribosomal stalk, which, however, is not functionally equivalent to the endogenous one.
Gagou
M E
ME
University of Athens, Department of Biology, Division of Genetics and Biotechnology, Panepistimiopolis, Kouponia, 15701 Athens, Greece.
Rodriguez Gabriel
M A
MA
Ballesta
J P
JP
Kouyanou
S
S
D000818:Animals; D015153:Blotting, Western; D002455:Cell Division; D002470:Cell Survival; D004175:Diptera / Q000166:cytology / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015870:Gene Expression; D005816:Genetic Complementation Test; D006863:Hydrogen-Ion Concentration; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007525:Isoelectric Focusing; D008958:Models, Molecular; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism*
D005656:Fungal Proteins; D019476:Insect Proteins; D010750:Phosphoproteins; D012269:Ribosomal Proteins; C031937:phosphoprotein P2, ribosomal; C035690:ribosomal phosphoprotein P1; C054675:ribosomal protein P0