Intron requirement for AFP gene expression in Trichoderma viride.
The 430 bp ORF of the Aspergillus giganteus antifungal protein (AFP) gene, containing two small introns, was fused between the promoter and the terminator of the Aspergillus nidulans trpC gene. The AFP gene in this vector produced detectable levels of spliced mRNA in Trichoderma viride. In contrast, in the same vector configuration, its 285 bp intronless derivative showed no accumulation of mRNA when transformed into T. viride. Such expression results were confirmed at the protein level. This fact demonstrated that the introns were required for AFP gene expression in T. viride. This is thought to be a novel phenomenon found in filamentous fungi. Although the mechanism of splicing in filamentous fungi might be similar to that in other eukaryotes, little is known of how it affects expression. This study suggests that the small introns in filamentous fungal genes may not only act as intervening elements, but may also play crucial roles in gene expression by affecting mRNA accumulation. Furthermore, it may provide new evidence for intron-dependent evolution.
State Key Laboratory of Molecular Biology, Box 16, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, PR China.
Jun
J
Xu
State Key Laboratory of Molecular Biology, Box 16, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, PR China.
Zhen Zhen
ZZ
Gong
D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D007438:Introns; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D012326:RNA Splicing; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic; D014170:Transformation, Genetic; D014242:Trichoderma / Q000235:genetics*
D005656:Fungal Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; C097609:antifungal protein, Aspergillus