P-acquiring auxiliary metabolic genes
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ABSTRACT:
PROVIDER: PRJEB60228 | ENA |
REPOSITORIES: ENA
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Project description:Cyanophages infecting the marine cyanobacteria Prochlorococcus and Synechococcus encode and express genes for the photosynthetic light reactions. Sequenced cyanophage genomes lack Calvin cycle genes, however, suggesting that photosynthetic energy harvested via phage proteins is not used for carbon fixation. We report here that cyanophages carry and express a Calvin cycle inhibitor, CP12, whose host homologue directs carbon flux from the Calvin cycle to the pentose phosphate pathway (PPP). Phage CP12 was coexpressed with phage genes involved in the light reactions, deoxynucleotide biosynthesis, and the PPP, including a transaldolase gene that is the most prevalent PPP gene in cyanophages. Phage transaldolase was purified to homogeneity from several strains and shown to be functional in vitro, suggesting that it might facilitate increased flux through this key reaction in the host PPP, augmenting production of NADPH and ribose 5-phosphate. Kinetic measurements of phage and host transaldolases revealed that the phage enzymes have k(cat)/K(m) values only approximately one third of the corresponding host enzymes. The lower efficiency of phage transaldolase may be a tradeoff for other selective advantages such as reduced gene size: we show that more than half of host-like cyanophage genes are significantly shorter than their host homologues. Consistent with decreased Calvin cycle activity and increased PPP and light reaction activity under infection, the host NADPH/NADP ratio increased two-fold in infected cells. We propose that phage-augmented NADPH production fuels deoxynucleotide biosynthesis for phage replication, and that the selection pressures molding phage genomes involve fitness advantages conferred through mobilization of host energy stores.
| S-EPMC3182688 | biostudies-literature
Project description:Viral contigs assembled from mine tailings metagenomes
| PRJEB78842 | ENA
Project description:Viral contigs associated with Trinidad Haemagogus mosquitoes
| PRJNA689580 | ENA
Project description:metagenomic contigs from dromedary fecal sample library
| PRJEB19201 | ENA
Project description:In the recent years, RNA silencing has been studied extensively to be a conserved regulatory process in plants. In the antiviral silencing, the intermediate double-stranded RNA form during the replication of RNA viruses were recognized and processed into abundant of overlapping viral siRNA (viRNAs). Accordingly, the cloned viRNAs could be conversely assembled into some contigs of viruses, which is recently exploited for identifying new viruses and their genome sequences.To obtain rapidly the complete genome sequence of BYSMV, we carried out deep sequencing of small RNAs from healthy and BYSMV infected wheat, respectively. Thirteen contigs were assembled from the overlapping viRNAs only present in the infected wheat but not in the healthy wheat. The results of BLAST showed that ten contigs shared about 96% identity with the reported L gene of BYSMV isolate Zanjan-1. Viral assembly from the BYSMV infected wheat plants to obtain the full lengh genome and characterise the viral siRNAs
2015-09-15 | E-GEOD-61565 | biostudies-arrayexpress
Project description:Auxiliary metabolic genes (AMG) are commonly found in the genomes of phages that infect cyanobacteria and increase the fitness of the cyanophage. AMGs are often homologs of host genes, and also typically related to photosynthesis. For example, the ΦcpeT gene in the cyanophage P-HM1 encodes a putative phycobiliprotein lyase related to cyanobacterial T-type lyases, which facilitate attachment of linear tetrapyrrole chromophores to Cys-155 of phycobiliprotein β-subunits, suggesting that ΦCpeT may also help assemble light-harvesting phycobiliproteins during infection. To investigate this possibility, we structurally and biochemically characterized recombinant ΦCpeT. The solved crystal structure of ΦCpeT at 1.8-Å resolution revealed that the protein adopts a similar fold as the cyanobacterial T-type lyase CpcT from Nostoc sp. PCC7120 but overall is more compact and smaller. ΦCpeT specifically binds phycoerythrobilin (PEB) in vitro leading to a tight complex that can also be formed in Escherichia coli when it is co-expressed with genes encoding PEB biosynthesis (i.e. ho1 and pebS). The formed ΦCpeT·PEB complex was very stable as the chromophore was not lost during chromatography and displayed a strong red fluorescence with a fluorescence quantum yield of ΦF = 0.3. This complex was not directly able to transfer PEB to the host phycobiliprotein β-subunit. However, it could assist the host lyase CpeS in its function by providing a pool of readily available PEB, a feature that might be important for fast phycobiliprotein assembly during phage infection.
| S-EPMC5336146 | biostudies-literature
Project description:In the recent years, RNA silencing has been studied extensively to be a conserved regulatory process in plants. In the antiviral silencing, the intermediate double-stranded RNA form during the replication of RNA viruses were recognized and processed into abundant of overlapping viral siRNA (viRNAs). Accordingly, the cloned viRNAs could be conversely assembled into some contigs of viruses, which is recently exploited for identifying new viruses and their genome sequences.To obtain rapidly the complete genome sequence of BYSMV, we carried out deep sequencing of small RNAs from healthy and BYSMV infected wheat, respectively. Thirteen contigs were assembled from the overlapping viRNAs only present in the infected wheat but not in the healthy wheat. The results of BLAST showed that ten contigs shared about 96% identity with the reported L gene of BYSMV isolate Zanjan-1.
2015-09-15 | GSE61565 | GEO
Project description:Contigs metagenomic, de novo assembly of consortium reads
| PRJNA413159 | ENA
Project description:For the abundant marine Alphaproteobacterium Pelagibacter (SAR11), and other bacteria, phages are powerful forces of mortality. However, little is known about the most abundant Pelagiphages in nature, such as the widespread HTVC023P-type, which is currently represented by two cultured phages. Using viral metagenomic data sets and fluorescence-activated cell sorting, we recovered 80 complete, undescribed Podoviridae genomes that form 10 phylogenomically distinct clades (herein, named Clades I to X) related to the HTVC023P-type. These expanded the HTVC023P-type pan-genome by 15-fold and revealed 41 previously unknown auxiliary metabolic genes (AMGs) in this viral lineage. Numerous instances of partner-AMGs (colocated and involved in related functions) were observed, including partners in nucleotide metabolism, DNA hypermodification, and Curli biogenesis. The Type VIII secretion system (T8SS) responsible for Curli biogenesis was identified in nine genomes and expanded the repertoire of T8SS proteins reported thus far in viruses. Additionally, the identified T8SS gene cluster contained an iron-dependent regulator (FecR), as well as a histidine kinase and adenylate cyclase that can be implicated in T8SS function but are not within T8SS operons in bacteria. While T8SS are lacking in known Pelagibacter, they contribute to aggregation and biofilm formation in other bacteria. Phylogenetic reconstructions of partner-AMGs indicate derivation from cellular lineages with a more recent transfer between viral families. For example, homologs of all T8SS genes are present in syntenic regions of distant Myoviridae Pelagiphages, and they appear to have alphaproteobacterial origins with a later transfer between viral families. The results point to an unprecedented multipartner-AMG transfer between marine Myoviridae and Podoviridae. Together with the expansion of known metabolic functions, our studies provide new prospects for understanding the ecology and evolution of marine phages and their hosts. IMPORTANCE One of the most abundant and diverse marine bacterial groups is Pelagibacter. Phages have roles in shaping Pelagibacter ecology; however, several Pelagiphage lineages are represented by only a few genomes. This paucity of data from even the most widespread lineages has imposed limits on the understanding of the diversity of Pelagiphages and their impacts on hosts. Here, we report 80 complete genomes, assembled directly from environmental data, which are from undescribed Pelagiphages and render new insights into the manipulation of host metabolism during infection. Notably, the viruses have functionally related partner genes that appear to be transferred between distant viruses, including a suite that encode a secretion system which both brings a new functional capability to the host and is abundant in phages across the ocean. Together, these functions have important implications for phage evolution and for how Pelagiphage infection influences host biology in manners extending beyond canonical viral lysis and mortality.
| S-EPMC9599517 | biostudies-literature