Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/9/2008
Publication Date: 3/9/2008
Citation: Brown, D.W., Butchko, R.A., Ma, L. 2008. Survey of mRNA Isoforms in Fusarium Verticillioides by ESTs: Alternative Splicing is Part of the Story [abstract]. European Conference on Fungal Genetics. PR1.59. Interpretive Summary:
Technical Abstract: The filamentous fungus Fusarium verticillioides is a pathogen of maize and synthesizes a number of economically important toxins including fumonisins. Fumonisins cause a variety of animal diseases and have been shown to cause cancer in some animals. Contaminated maize and maize products lead to substantial losses to farmers each year. The transcriptional and posttranscriptional regulatory mechanisms controlling fungal pathogenesis and toxin production are poorly understood. Analysis of over 87,000 F. verticillioides ESTs identified a total of 578 genes with one or more mRNA isoforms and is equivalent to 6.3% of the genes represented. The most common isoform found correspond to alternatively spliced transcripts. Alternative splicing (AS) in higher eukaryotes play a critical role in expanding gene function by increasing protein diversity and by affecting mRNA stability. The different AS forms (ASF) include intron retention (73%), alternative donor or acceptor sites (25%), and exon skipping (2%). The percentage of genes with ASFs and the ratio of different ASFs is substantial different than that found in mammals and plants. Preliminary analysis of predicted open reading frames found that 28% of the AS events could generate altered proteins while 54% introduce frame shifts or stop codons and 16% were in 5’ or 3’ non-coding sequences. Transcript isoforms were also found that reflect multiple transcriptional initiation start as well as termination sites. And finally, we found sets of antisense RNA transcripts of which some have ASFs including retained introns and alternative donor and acceptor sites. Analysis of the Fusarium transcriptome indicate a complexity previously not described and the continued study of ASFs and their possible function will aid our understanding of fungal gene regulation.