Maltose permease-encoding mRNA is cleaved in Aspergillus oryzae

Ref ID: 18350

Author:

Mizuki Tanaka, Takahiro Shintani, and Katsuya Gomi

Author address:

Graduate School of
Agricultural Science, Tohoku University, Japan

Full conference title:

Asperfest 8

Abstract:

Eukaryotic mRNA is degraded by two degradation pathways: the 5 L to 3 L degaradation pathway by Xrn1 and the 3 L to 5 L degradation pathway by
exosome-Ski complex. To investigate the mRNA degradation mechanism in filamentous fungi, we generated the disruptions of orthologous genes
encoding mRNA degradation machinery in A. oryzae. Interestingly, the disruptants of ski2 and ski3, components of Ski complex, showed the remarkable
growth defect on minimal medium containing maltose or starch as a sole carbon source, whereas they normally grew on the medium with glucose or
fructose as a sole carbon source. Northern blot analysis showed that the 3 L-truncated fragment of mRNA encoding maltose permease (malP) was
accumulated in Ski complex deficient mutants. Circularized RT- PCR analysis revealed that the malP mRNA was cleaved at a large stem-loop structure
situated within the coding region. Since the 3 L-truncated malP mRNA has no translational termination codon, it would be recognized by a certain
ribosome releasing factor(s). We thus generated the gene disruptant of HbsA, ortholog of yeast Hbs1 identified as a recognition factor of aberrant mRNA
in which ribosome was stalled in translation elongation. In a hbsA disruptant, the 3 L-truncated malP mRNA was accumulated, and its degradation was
suppressed. These results indicate that the malP mRNA is cleaved by endonuclease and the 3 L-truncated malP mRNA is degraded rapidly by HbsAdependent 3 L to 5 L degradation pathway.

Abstract Number: 28)

Conference Year: 2011

Link to conference website: NULL

New link: NULL

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