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Lau SKP, Chow WN, Wong AYP, Yeung JMY, Bao J, Zhang N, Lok S, Woo PCY, Yuen KY. Identification of microRNA-like RNAs in mycelial and yeast phases of the thermal dimorphic fungus Penicillium marneffei. PLoS Negl Trop Dis 2013; 7:e2398. [PMID: 23991243 PMCID: PMC3749987 DOI: 10.1371/journal.pntd.0002398] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/19/2013] [Indexed: 01/16/2023] Open
Abstract
Background Penicillium marneffei is the most important thermal dimorphic fungus causing systemic mycosis in China and Southeast Asia. While miRNAs are increasingly recognized for their roles in post-transcriptional regulation of gene expression in animals and plants, miRNAs in fungi were less well studied and their potential roles in fungal dimorphism were largely unknown. Based on P. marneffei genome sequence, we hypothesize that miRNA-like RNAs (milRNAs) may be expressed in the dimorphic fungus. Methodology/Principal Findings We attempted to identify milRNAs in P. marneffei in both mycelial and yeast phase using high-throughput sequencing technology. Small RNAs were more abundantly expressed in mycelial than yeast phase. Sequence analysis revealed 24 potential milRNA candidates, including 17 candidates in mycelial and seven in yeast phase. Two genes, dcl-1 and dcl-2, encoding putative Dicer-like proteins and the gene, qde-2, encoding Argonaute-like protein, were identified in P. marneffei. Phylogenetic analysis showed that dcl-2 of P. marneffei was more closely related to the homologues in other thermal dimorphic pathogenic fungi than to Penicillium chrysogenum and Aspergillus spp., suggesting the co-evolution of dcl-2 among the thermal dimorphic fungi. Moreover, dcl-2 demonstrated higher mRNA expression levels in mycelial than yeast phase by 7 folds (P<0.001). Northern blot analysis confirmed the expression of two milRNAs, PM-milR-M1 and PM-milR-M2, only in mycelial phase. Using dcl-1KO, dcl-2KO, dclDKO and qde-2KO deletion mutants, we showed that the biogenesis of both milRNAs were dependent on dcl-2 but not dcl-1 or qde-2. The mRNA expression levels of three predicted targets of PM-milR-M1 were upregulated in knockdown strain PM-milR-M1KD, supporting regulatory function of milRNAs. Conclusions/Significance Our findings provided the first evidence for differential expression of milRNAs in different growth phases of thermal dimorphic fungi and shed light on the evolution of fungal proteins involved in milRNA biogenesis and possible role of post-transcriptional control in governing thermal dimorphism. Penicillium marneffei is the most important thermal dimorphic pathogenic fungus in Southeast Asia. Despite findings on diverse genes and mechanisms involved in dimorphic switching, the key to signally pathways governing the switch is still unknown. Since miRNAs are important regulatory molecules in eukaryotes, we attempt to define if miRNAs are expressed in different growth phases of P. marneffei. Using high-throughput sequencing, we identified 24 potential milRNA candidates in P. marneffei, which were more abundantly expressed in mycelial than yeast phase. Two genes, dcl-1 and dcl-2, encoding Dicer-like proteins and the gene, qde-2, encoding Argonaute-like protein, were also identified. Phylogenetic analysis showed that dcl-2 of P. marneffei was more closely related to the homologues in other thermal dimorphic pathogenic fungi than to Penicillium chrysogenum and Aspergillus spp.. dcl-2 demonstrated higher mRNA levels in mycelial than yeast phase. Northern blot analysis confirmed expression of two milRNAs, PM-milR-M1 and PM-milR-M2, only in mycelial phase, whose expression was dependent on dcl-2 but not dcl-1 or qde-2. The mRNA levels of three predicted targets of PM-milR-M1 were upregulated in knockdown strain PM-milR-M1KD, supporting its regulatory function. This study represents the first discovery of milRNAs in thermal dimorphic fungi, with differential expression in different growth phases.
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Affiliation(s)
- Susanna K. P. Lau
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Wang-Ngai Chow
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Annette Y. P. Wong
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Julian M. Y. Yeung
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Jessie Bao
- Genome Research Centre, The University of Hong Kong, Hong Kong, China
| | - Na Zhang
- Genome Research Centre, The University of Hong Kong, Hong Kong, China
| | - Si Lok
- Genome Research Centre, The University of Hong Kong, Hong Kong, China
| | - Patrick C. Y. Woo
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- * E-mail: (PCYW); (KYY)
| | - Kwok-Yung Yuen
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- * E-mail: (PCYW); (KYY)
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Vaughn JN, Ellingson SR, Mignone F, von Arnim A. Known and novel post-transcriptional regulatory sequences are conserved across plant families. RNA (NEW YORK, N.Y.) 2012; 18:368-84. [PMID: 22237150 PMCID: PMC3285926 DOI: 10.1261/rna.031179.111] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The sequence elements that mediate post-transcriptional gene regulation often reside in the 5' and 3' untranslated regions (UTRs) of mRNAs. Using six different families of dicotyledonous plants, we developed a comparative transcriptomics pipeline for the identification and annotation of deeply conserved regulatory sequences in the 5' and 3' UTRs. Our approach was robust to confounding effects of poor UTR alignability and rampant paralogy in plants. In the 3' UTR, motifs resembling PUMILIO-binding sites form a prominent group of conserved motifs. Additionally, Expansins, one of the few plant mRNA families known to be localized to specific subcellular sites, possess a core conserved RCCCGC motif. In the 5' UTR, one major subset of motifs consists of purine-rich repeats. A distinct and substantial fraction possesses upstream AUG start codons. Half of the AUG containing motifs reveal hidden protein-coding potential in the 5' UTR, while the other half point to a peptide-independent function related to translation. Among the former, we added four novel peptides to the small catalog of conserved-peptide uORFs. Among the latter, our case studies document patterns of uORF evolution that include gain and loss of uORFs, switches in uORF reading frame, and switches in uORF length and position. In summary, nearly three hundred post-transcriptional elements show evidence of purifying selection across the eudicot branch of flowering plants, indicating a regulatory function spanning at least 70 million years. Some of these sequences have experimental precedent, but many are novel and encourage further exploration.
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Affiliation(s)
- Justin N. Vaughn
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Sally R. Ellingson
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Flavio Mignone
- Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Università degli Studi di Milano, 20133 Milano, Italy
| | - Albrecht von Arnim
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee 37996, USA
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Tennessee 37996, USA
- Corresponding author.E-mail .
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