The human homologue of the mouse Surf5 gene encodes multiple alternatively spliced transcripts.
ABSTRACT Hu-Surf5 is included within the Surfeit locus, a cluster of six genes originally identified in mouse. In the present study, we have cloned and characterized the Hu-Surf5 gene and its mRNA multiple transcripts. Comparison of the most abundant cDNA and genomic sequence shows that the Hu-Surf5 is spread over a region of approximately 7.5 kb and consists of five exons separated by four introns. The nucleotide sequence of the genomic region flanking the 3'-end of the Hu-Surf5 gene revealed the presence of a processed pseudogene of human ribosomal protein L21 followed by Hu-Surf6 gene. Only 110 bp separate the transcription start site of Hu-Surf5 and Hu-Surf3/L7a gene and the transcription direction is divergent. Earlier studies defined the 110 bp region essential for promoter activity of Hu-Surf3/L7a. Here, we show that this region stimulates transcription with a slightly different efficiency in both directions. The bidirectional promoter lacks an identifiable TATA box and is characterized by a CpG island that extends through the first exon into the first intron of both genes. These features are characteristic of housekeeping genes and are consistent with the wide tissue distribution observed for Hu-Surf5 expression. Hu-Surf5 encodes three different transcripts, Surf-5a, Surf-5b, and Surf-5c, which result from alternative splicing. Two protein products, SURF-5A and SURF-5B have been characterized. Production of chimaeras between the full-length SURF-5A or SURF-5B and the green fluorescent protein (GFP) allowed to localize both proteins in the cytoplasm.
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ABSTRACT: The organization and large size of the mammalian cell genome allows spatial separation of different transcription units. In those cases where more than one species of messenger are synthesized from the same cellular DNA sequence, they have been found to be generated from transcription proceeding in the same direction. These mRNAs always share regions of homology and can differ from one another as a result of differential processing (splicing and/or polyadenylation) or alternative initiation. In contrast, complementary mRNAs transcribed from opposite strands of the same cellular DNA sequence have not previously been observed. Here we have identified a region of mouse DNA at which processed mRNAs from two adjacent convergent transcription units overlap by 133 base pairs (bp) at their 3'-untranslated ends. One of the transcription units appears to encode a second mRNA which does not contain this overlapping region. This represents the first description of the natural occurrence of processed mammalian cell mRNAs transcribed from opposite strands of the same DNA sequence. The implications of these complementary regions in normal gene regulation are discussed in the context of the finding that the artificial introduction into cells of DNA constructs synthesizing anti-sense RNAs complementary to regions of mRNA transcribed from a chromosomal gene, can inhibit the gene's activity, presumably by the formation of double-stranded RNA.Nature 01/1986; 322(6076):275-9. · 38.60 Impact Factor
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- Cell 06/1977; 11(1):223-32. · 31.96 Impact Factor