Isolation and expression of the genes encoding the acidic ribosomal phosphoproteins P1 and P2 of the medfly Ceratitis capitata

The genes of the acidic ribosomal proteins P1 and P2 (CcP1 and CcP2) of the medfly Ceratitis capitata were isolated from a genomic library using homol ogue DNA probes prepared by PCR. Sequencing and characterization of the two genes revealed strong similarities of the encoded amino acid sequence to t he homologous proteins of Drosophila melanogaster and other eukaryotic spec ies. The predicted amino acid sequences of the CcP1 and CcP2 proteins share d an almost identical carboxyl terminal sequence of 10 amino acids common t o most known acidic ribosomal proteins. The CcP2 gene lacked intervening se quences in contrast to the CcP1 gene, which was interrupted by an intron of 188 nucleotides. Both genes were cloned in expression pT7 vectors and were expressed in Escherichia coil. The 17- and 15-kDa recombinant proteins rea cted with a monoclonal antibody specific to the highly conserved carboxyl t erminus of eukaryotic acidic ribosomal proteins, confirming their equivalen ce to these ribosomal components. Both recombinant proteins were electropho retically identical to acidic proteins extracted from purified ribosomes of C. capitata. (C) 1999 Elsevier Science B.V. All rights reserved.