Genome-wide characterization of methylguanosine-capped and polyadenylated small RNAs in the rice blast fungus Magnaporthe oryzae

Nucleic Acids Res. 2010 Nov;38(21):7558-69. doi: 10.1093/nar/gkq583. Epub 2010 Jul 21.

Abstract

Small RNAs are well described in higher eukaryotes such as mammals and plants; however, knowledge in simple eukaryotes such as filamentous fungi is limited. In this study, we discovered and characterized methylguanosine-capped and polyadenylated small RNAs (CPA-sRNAs) by using differential RNA selection, full-length cDNA cloning and 454 transcriptome sequencing of the rice blast fungus Magnaporthe oryzae. This fungus causes blast, a devastating disease on rice, the principle food staple for over half the world's population. CPA-sRNAs mapped primarily to the transcription initiation and termination sites of protein-coding genes and were positively correlated with gene expression, particularly for highly expressed genes including those encoding ribosomal proteins. Numerous CPA-sRNAs also mapped to rRNAs, tRNAs, snRNAs, transposable elements and intergenic regions. Many other 454 sequence reads could not be mapped to the genome; however, inspection revealed evidence for non-template additions and chimeric sequences. CPA-sRNAs were independently confirmed using a high affinity variant of eIF-4E to capture 5'-methylguanosine-capped RNA followed by 3'-RACE sequencing. These results expand the repertoire of small RNAs in filamentous fungi.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Fungal Proteins / genetics
  • Genome, Fungal
  • Guanosine / analogs & derivatives*
  • Guanosine / analysis
  • Magnaporthe / genetics*
  • Molecular Sequence Data
  • Poly A / analysis*
  • RNA Caps / chemistry*
  • RNA Polymerase I / metabolism
  • RNA Polymerase II / metabolism
  • RNA, Fungal / chemistry
  • RNA, Fungal / genetics
  • RNA, Fungal / metabolism
  • RNA, Small Untranslated / chemistry*
  • RNA, Small Untranslated / genetics
  • RNA, Small Untranslated / metabolism
  • Repetitive Sequences, Nucleic Acid

Substances

  • 8-methylguanosine
  • Fungal Proteins
  • RNA Caps
  • RNA, Fungal
  • RNA, Small Untranslated
  • Guanosine
  • Poly A
  • RNA Polymerase II
  • RNA Polymerase I