Primary sequence and evolutionary conservation of ribosomal protein genes from the domestic cat

Splice-site pairing is an intrinsically high fidelity process

The extensive alternative splicing in higher eukaryotes has initiated a debate whether alternative mRNA isoforms are generated by an inaccurate spliceosome or are the consequence of highly degenerate splice sites within the human genome. Here, we established a quantitative assay to evaluate the accuracy of splice-site pairing by determining the number of incorrect exon-skipping events made from constitutively spliced pre-mRNA transcripts. We demonstrate that the spliceosome pairs exons with an astonishingly high degree of accuracy that may be limited by the quality of pre-mRNAs generated by RNA pol II. The error rate of exon pairing is increased by the effects of the neurodegenerative disorder spinal muscular atrophy because of reduced levels of Survival of Motor Neuron, a master assembler of spliceosomal components. We conclude that all multi-intron-containing genes are alternatively spliced and that the reduction of SMN results in a general splicing defect that is mediated through alterations in the fidelity of splice-site pairing.

Isolation and characterization of medaka ribosomal protein S3a (fte-1) cDNA and gene

Many ribosomal protein genes were cloned from different organisms. We describe here, for the first time, the isolation of the ribosomal protein S3a cDNA and gene from a teleost - the medaka (Oryzias latipes). The cDNA sequence is 863bp long and encodes an open reading frame of 266 amino acids. The gene is 2927bp long and contains six introns and five introns. The levels of the S3a mRNA are elevated during embryonal development. Transcription of the gene was also detected in different tissues of adult medaka. At the 5' untranslated region of the cDNA, the terminal pyrimidine tract, a common feature with all ribosomal protein genes, was found. snoRNA sequences were found in introns 3 and 5, similar to human and mouse U73b and U73a.