THE DROSOPHILA-MELANOGASTER HOMOLOG OF RIBOSOMAL-PROTEIN S18

The sequence of the cDNA encoding the Drosophila melanogaster homolog of the human and rat small-subunit ribosomal protein, S18 (rpS18), is presented. The deduced 152-amino-acid (aa) sequence exhibits 76% ident ity to that of the human and rat rpS18 (152 aa), and is, like them, a member of the larger rpS13 family which includes archaebacterial, euba cterial and plant mitochondrial (mt) rpS13. The D. melanogaster rpS18 gene is single copy and maps at 56F, a chromosome region encompassing a previously characterised Minute locus, M(2)56F. The rpS18 gene gives rise to a single 700-nucleotide transcript present throughout develop ment, A comparison of the rpS13 family members suggests that conservat ion is greatest at the N- and C-termini, whilst additional insertions are present in the Drosophila, mammalian and archaebacterial proteins relative to the eubacterial and plant mt proteins.