Sequence of a cDNA from the mosquito Anopheles gambiae encoding a homologue of human ribosomal protein S7.

Studies of ribosomal proteins have given insight to the function and structure of the ribosome. During ribosome assembly, individual ribosomal proteins that initially recognize rRNA must bind to the assembly particle in a certain order and work cooperatively, rather than independently (1). Two of these important ribosomal proteins are S7 and S8. Detailed study of these and other ribosomal proteins is vital to the understanding of protein synthesis. Here we report the structure, chromosome location and complete sequence of a cDNA in the mosquito Anopheles gambiae encoding a homologue of the human ribosomal S7 protein. The clone was isolated from a cDNA library constructed using poly(A) RNA of adult female and male mosquitoes from the G3 strain of A.gambiae (2). The complete 817 nucleotidelong cDNA contains a continuous open reading frame of 193 codons which potentially encodes a peptide with a molecular weight of 22206.90 Daltons and an isoelectric point of 9.945. Furthermore, this peptide shows a high level of basic amino acids (37), consistent with characterizations of S7 and S8-like proteins in other organisms (3). A presumed polyadenylation signal, AATAAA is located at bases 771-776. At the amino acid level, the open reading frame shows 71.7% identity with human ribosomal protein S7; 70.6% identity with Xenopus laevis ribosomal protein S8, and 61.7% identity with rat ribosomal protein S8 (Figure 1). Nucleotide comparison of the A.gambiae ribosomal protein cDNA coding sequence reveals a 66.7% identity with human ribosomal protein S7, but there are no evident similarities among the 5' or 3' non-coding sequences. In situ hybridization to the ovarian nurse cell polyrene chromosomes of A.gambiae revealed its location at division 38B in the A.gambiae genome. REFERENCES