Project description:Here, we established for the first time a proteomic analysis of B. methanolicus MGA3, and we used this approach to compare cells grown on methanol and mannitol at 50°C as well as cells grown on methanol at 37°C and 50°C. Bacillus methanolicus MGA3 is a facultative methylotroph of industrial relevance that is able to grow on methanol as its sole source of carbon and energy. The Gram-positive bacterium possesses a soluble NAD-dependent methanol dehydrogenase and assimilates formaldehyde via the ribulose monophosphate (RuMP) cycle. We used label-free quantitative proteomics to generate reference proteome data for this bacterium and compared the proteome of B. methanolicus MGA3 on two different carbon sources (methanol and mannitol) as well as two different growth temperatures (50°C and 37°C). From a total of approximately 1,200 different detected proteins, approximately 1,000 of these were used for quantification. While the levels of 213 proteins were significantly different at the two growth temperatures tested, the levels of 109 proteins changed significantly when cells were grown on different carbon sources. The carbon source strongly affected the expression of enzymes related to carbon metabolism, and in particular, both dissimilatory and assimilatory RuMP cycle enzyme levels were elevated during growth on methanol compared to mannitol. Our data also indicate that B. methanolicus has a functional TCA cycle that is differentially regulated on mannitol and methanol. Other proteins presumed to be involved in growth on methanol were constitutively expressed under the different growth conditions. Protein Identification: Raw data of gel slices with equal molecular weight were loaded together into the software package Progenesis LCMS Version. 4.1 (www.nonlinear.com), a software tool developed for label-free quantification of LC–MS data. Data was analyzed according to Progenesis LCMS analysis in Weisser et al., In brief, for data loading, the option "High Mass Accuracy Instrument" was selected. LC–MS data were normalized and aligned according to manufacturer’s specifications. In the aligning step manual seeding of "three to five" vectors along the retention time gradient was performed followed by automatic alignment. For the identification of peptide features in the corresponding mass spectrometry files, Mascot generic files (.mgf file format) are generated with Progenesis LCMS (using up to five tandem mass spectra for each feature with the top 200 fragment ion peaks ,charge deconvolution and de-isotopting activated). Mgf files were searched by Mascot 2.3 search engine against an amino acid database containing 20,399 entries including 3,418 MGA3 annotated proteins (downloaded from Uniprot on August 2013), 6,651 yeast proteins, 261 known mass spectrometry contaminants as forward entries and from all forward entries except the contaminats, a reverse decoy sequence. Parameters for precursor tolerance and fragment ion tolerance were set to ± 10 ppm and ± 0.6 Da, respectively. Mascot results were loaded into Scaffold v4.05, using the options for protein clustering and high mass accuracy PeptideProphet scoring.

Project description:The genome of recombinant adeno-associated virus 2 (rAAV2) remains a promising candidate for gene therapy for cystic fibrosis (CF) lung disease, but due to limitations in the packaging capacity and the tropism of this virus with respect to the airways, strategies have evolved for packaging an rAAV2 genome (up to 5.8 kb) into the capsid of human bocavirus 1 (HBoV1) to produce a chimeric rAAV2/HBoV1 vector. Although a replication-incompetent HBoV1 genome has been established as a trans helper for capsid complementation, this system remains suboptimal with respect to virion yield. Here, a streamlined production system is described based on knowledge of the involvement of HBoV1 nonstructural (NS) proteins NS1, NS2, NS3, NS4, and NP1 in the process of virion production. The analyses reveal that NS1 and NS2 negatively impact virion production, NP1 is required to prevent premature termination of transcription of the cap mRNA from the native genome, and silent mutations within the polyadenylation sites of the cap coding sequence can eliminate this requirement for NP1. It is further shown that preventing the expression of all NS proteins significantly increases virion yield. Whereas the expression of capsid proteins VP1, VP2, and VP3 from a codon-optimized cap mRNA was highly efficient, optimal virion assembly, and thus potency, required enhanced VP1 expression, entailing a separate VP1 expression cassette. The final NS protein-free production system uses three-plasmid co-transfection of HEK293 cells, with one trans helper plasmid encoding VP1 and the AAV2 Rep proteins, and another encoding VP2-3 and components from adenovirus. This system yielded >16-fold more virions than the prototypic system, without reducing transduction potency. This increase in virion production is expected to facilitate greatly both research on the biology of rAAV2/HBoV1 and preclinical studies testing the effectiveness of this vector for gene therapy of CF lung disease in large animal models.

Project description:BackgroundBacillus methanolicus MGA3 is a thermophilic, facultative ribulose monophosphate (RuMP) cycle methylotroph. Together with its ability to produce high yields of amino acids, the relevance of this microorganism as a promising candidate for biotechnological applications is evident. The B. methanolicus MGA3 genome consists of a 3,337,035 nucleotides (nt) circular chromosome, the 19,174 nt plasmid pBM19 and the 68,999 nt plasmid pBM69. 3,218 protein-coding regions were annotated on the chromosome, 22 on pBM19 and 82 on pBM69. In the present study, the RNA-seq approach was used to comprehensively investigate the transcriptome of B. methanolicus MGA3 in order to improve the genome annotation, identify novel transcripts, analyze conserved sequence motifs involved in gene expression and reveal operon structures. For this aim, two different cDNA library preparation methods were applied: one which allows characterization of the whole transcriptome and another which includes enrichment of primary transcript 5'-ends.ResultsAnalysis of the primary transcriptome data enabled the detection of 2,167 putative transcription start sites (TSSs) which were categorized into 1,642 TSSs located in the upstream region (5'-UTR) of known protein-coding genes and 525 TSSs of novel antisense, intragenic, or intergenic transcripts. Firstly, 14 wrongly annotated translation start sites (TLSs) were corrected based on primary transcriptome data. Further investigation of the identified 5'-UTRs resulted in the detailed characterization of their length distribution and the detection of 75 hitherto unknown cis-regulatory RNA elements. Moreover, the exact TSSs positions were utilized to define conserved sequence motifs for translation start sites, ribosome binding sites and promoters in B. methanolicus MGA3. Based on the whole transcriptome data set, novel transcripts, operon structures and mRNA abundances were determined. The analysis of the operon structures revealed that almost half of the genes are transcribed monocistronically (940), whereas 1,164 genes are organized in 381 operons. Several of the genes related to methylotrophy had highly abundant transcripts.ConclusionThe extensive insights into the transcriptional landscape of B. methanolicus MGA3, gained in this study, represent a valuable foundation for further comparative quantitative transcriptome analyses and possibly also for the development of molecular biology tools which at present are very limited for this organism.

Dataset Information

Establishment of a functional system for recombinant production of secreted proteins at 50 °C in the thermophilic Bacillus methanolicus.

Publications

Establishment of a functional system for recombinant production of secreted proteins at 50 °C in the thermophilic Bacillus methanolicus.

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