Ribosomal protein L7a is encoded by a gene (Surf-3) within the tightly clustered mouse surfeit locus.
The mouse Surfeit locus, which contains a cluster of at least four genes (Surf-1 to Surf-4), is unusual in that adjacent genes are separated by no more than 73 base pairs (bp). The heterogeneous 5' ends of Surf-1 and Surf-2 are separated by only 15 to 73 bp, the 3' ends of Surf-1 and Surf-3 are only 70 bp apart, and the 3' ends of Surf-2 and Surf-4 overlap by 133 bp. This very tight clustering suggests a cis interaction between adjacent Surfeit genes. The Surf-3 gene (which could code for a basic polypeptide of 266 amino acids) is a highly expressed member of a pseudogene-containing multigene family. By use of an anti-peptide serum (against the C-terminal nine amino acids of the putative Surf-3 protein) for immunofluorescence and immunoblotting of mouse cell components and by in vitro translation of Surf-3 cDNA hybrid-selected mRNA, the Surf-3 gene product was identified as a 32-kilodalton ribosomal protein located in the 60S ribosomal subunit. From its subunit location, gel migration, and homology with a limited rat ribosomal peptide sequence, the Surf-3 gene was shown to encode the mouse L7a ribosomal protein. The Surf-3 gene is highly conserved through evolution and was detected by nucleic acid hybridization as existing in multiple copies (multigene families) in other mammals and as one or a few copies in birds, Xenopus, Drosophila, and Schizosaccharomyces pombe. The Surf-3 C-terminal anti-peptide serum detects a 32-kilodalton protein in other mammals, birds, and Xenopus but not in Drosophila and S. pombe. The possible effect of interaction of the Surf-3 ribosomal protein gene with adjacent genes in the Surfeit locus at the transcriptional or posttranscriptional level or both levels is discussed.
Giallongo
A
A
Department of Eukaryotic Gene Organization and Expression, Imperial Cancer Research Fund, London, England.
Yon
J
J
Fried
M
M
D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D004274:DNA, Recombinant / Q000032:analysis; D005455:Fluorescent Antibody Technique; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D005810:Multigene Family; D011544:Pseudogenes; D051381:Rats; D012269:Ribosomal Proteins / Q000032:analysis / Q000235:genetics*; D012568:Schizosaccharomyces
D004274:DNA, Recombinant; C053634:RPL7 protein, human; D012269:Ribosomal Proteins; C512845:Rpl7 protein, mouse