A developmentally regulated gene encodes the dictyostelium homolog of yeast ribosomal protein S4 and mammalian LLRep3 proteins.
We report the sequence and expression of a single-copy gene from Dictyostelium discoideum which encodes the homolog of yeast ribosomal protein S4, a protein located on the small ribosomal subunit and known to play an important role in maintaining translational fidelity. Over a highly conserved central region, the Dictyostelium protein has 78% sequence similarity to the yeast protein and 83% sequence similarity to mammalian S4 protein homologs, the LLRep3 proteins. The Dictyostelium gene encodes a polypeptide 28,717 Da in size and hence this ribosomal protein has been named rp29. The N-terminal sequence of the Dictyostelium rp29 protein is extended by 61 amino acids and 14 amino acids compared to the mammalian and yeast proteins, respectively, and the C-terminus is correspondingly 15 amino acids or 2 amino acids shorter. Although the coding region of the rp29 gene is present on a single exon, a 157bp intron interrupts the 5' untranslated region and unusually contains four direct repeats of the sequence TCAATCT. The gene is expressed maximally during vegetative growth but a second peak of expression also occurs late in development which is restricted to prestalk cells; rp29 is the first Dictyostelium ribosomal protein gene reported which shows prestalk-specific developmental expression. During each round of expression, only a single 0.9kb transcript is produced which is similar in size to the yeast S4 ribosomal protein transcript (0.8kb) but markedly smaller than the mammalian LLRep3 mRNA (1.7kb) due to a much shorter 5' untranslated region.
Proffitt
J A
JA
Department of Biochemistry and Molecular Biology, University of Leeds, UK.
Jagger
P S
PS
Wilson
G A
GA
Donovan
J T
JT
Widdowson
D C
DC
Hames
B D
BD
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003062:Codon; D004271:DNA, Fungal; D004023:Dictyostelium / Q000235:genetics* / Q000254:growth & development; D005656:Fungal Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011061:Poly A / Q000235:genetics; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D016601:RNA-Binding Proteins; D015183:Restriction Mapping; D012269:Ribosomal Proteins / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013728:Terminator Regions, Genetic
D003062:Codon; D004271:DNA, Fungal; D005656:Fungal Proteins; D011506:Proteins; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins; C042040:ribosomal protein 29; C031798:ribosomal protein S4; C070085:LLREP3 protein, Dictyostelium discoideum; D011061:Poly A