Benefits of random-priming: Exhaustive survey of a cDNA library from lung tissue of a SARS patient

Abstract

The severe acute respiratory syndrome (SARS) leads to severe injury in the lungs with multiple factors, though the pathogenesis is still largely unclear. This paper describes the particular analyses of the transcriptome of human lung tissue that was infected by SARS-associated coronavirus (SARS-CoV). Random primers were used to produce ESTs from total RNA samples of the lung tissue. The result showed a high diversity of the transcripts, covering much of the human genome, including loci which do not contain protein coding sequences. 10,801 ESTs were generated and assembled into 267 contigs plus 7,659 singletons. Sequences matching to SARS-CoV RNAs and other pneumonia-related microbes were found. The transcripts were well classified by functional annotation. Among the 7,872 assembled sequences that were identified as from human genome, 578 non-coding genes were revealed by BLAST search. The transcripts were mapped to the human genome with the restriction of identity=100%, which found a candidate pool of 448 novel transcriptional loci where EST transcriptional signal was never found before. Among these, 13 loci were never reported to be transcriptional by other detection methods such as gene chips, tiling arrays, and paired-end ditags (PETs). The result showed that random-priming cDNA library is valid for the investigation of transcript diversity in the virus-infected tissue. The EST data could be a useful supplemental source for SARS pathology researches.