Summary: Birnavirus RNA dependent RNA polymerase (VP1)

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Wikipedia: Birnaviridae
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Birnaviridae Edit Wikipedia article

Birnaviridae
Virus classification
Group:	Group III (dsRNA)
Family:	Birnaviridae
Genera
Aquabirnavirus Avibirnavirus Blosnavirus Entomobirnavirus

Birnavirus RNA dependent RNA polymerase (VP1)

Identifiers

Symbol

Birna_RdRp

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

Birnavirus VP2 protein

crystal structure of infectious bursal disease virus vp2 subviral particle

Identifiers

Symbol

Birna_VP2

Pfam clan

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

Birnavirus VP3 protein

Identifiers

Symbol

Birna_VP3

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

Birnavirus VP4 protein

Identifiers

Symbol

Birna_VP4

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

Birnavirus VP5 protein

Identifiers

Symbol

Birna_VP5

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

The Birnaviridae are a family of viruses, including the following genera:

Genus Aquabirnavirus; type species: Infectious pancreatic necrosis virus
Genus Avibirnavirus; type species: Infectious bursal disease virus
Genus Blosnavirus; type species: Blotched snakehead virus
Genus Entomobirnavirus; type species: Drosophila X virus

The Birnaviridae are type-III viruses in the Baltimore classification, which means they have a double-stranded RNA genome. The other family of type-III viruses is the Reoviridae.

[edit] Birnaviridae proteins

The Birnaviridae genome encodes several proteins:

The Birnaviridae RNA-directed RNA polymerase (VP1), which lacks the highly conserved Gly-Asp-Asp (GDD) sequence, a component of the proposed catalytic site of this enzyme family that exists in the conserved motif VI of the palm domain of other RNA-directed RNA polymerases.^[1]

The large RNA segment, segment A, of birnaviruses codes for a polyprotein (N-VP2-VP4-VP3-C) ^[2] that is processed into the major structural proteins of the virion: VP2, VP3 (a minor structural component of the virus), and into the putative protease VP4.^[2] VP4 protein is involved in generating VP2 and VP3.^[2] recombinant VP3 is more immunogenic than recombinant VP2.^[3]

Infectious pancreatic necrosis virus (IPNV), a birnavirus, is an important pathogen in fish farms. Analyses of viral proteins showed that VP2 is the major structural and immunogenic polypeptide of the virus.^[4]^[5] All neutralizing monoclonal antibodies are specific to VP2 and bind to continuous or discontinuous epitopes. The variable domain of VP2 and the 20 adjacent amino acids of the conserved C-terminal are probably the most important in inducing an immune response for the protection of animals.^[4]

Non structural protein VP5 is found in RNA segment A. The function of this small viral protein is unknown. It is believed to be involved in influencing apoptosis, but studies are not completely concurring. The protein can not be found in the virion.

[edit] Viruses

The family includes a number of viruses:

Chicken proventricular necrosis virus

[edit] References

^ Shwed PS, Dobos P, Cameron LA, Vakharia VN, Duncan R (May 2002). "Birnavirus VP1 proteins form a distinct subgroup of RNA-dependent RNA polymerases lacking a GDD motif". Virology 296 (2): 241â50. doi:10.1006/viro.2001.1334. PMID 12069523.
^ ^a ^b ^c Jagadish MN, Staton VJ, Hudson PJ, Azad AA (March 1988). "Birnavirus precursor polyprotein is processed in Escherichia coli by its own virus-encoded polypeptide". J. Virol. 62 (3): 1084â7. PMC 253673. PMID 2828658. //www.ncbi.nlm.nih.gov/pmc/articles/PMC253673/.
^ Moon CH, Do JW, Cha SJ, Bang JD, Park MA, Yoo DJ, Lee JM, Kim HG, Chung DK, Park JW (October 2004). "Comparison of the immunogenicity of recombinant VP2 and VP3 of infectious pancreatic necrosis virus and marine birnavirus". Arch. Virol. 149 (10): 2059â68. PMID 15669113.
^ ^a ^b Heppell J, Tarrab E, Lecomte J, Berthiaume L, Arella M (December 1995). "Strain variability and localization of important epitopes on the major structural protein (VP2) of infectious pancreatic necrosis virus". Virology 214 (1): 40â9. doi:10.1006/viro.1995.9956. PMID 8525637.
^ Nobiron I, Galloux M, Henry C, Torhy C, Boudinot P, Lejal N, Da Costa B, Delmas B (February 2008). "Genome and polypeptides characterization of Tellina virus 1 reveals a fifth genetic cluster in the Birnaviridae family". Virology 371 (2): 350â61. doi:10.1016/j.virol.2007.09.022. PMID 17976679.

[edit] External links

Viralzone: Birnaviridae

This article incorporates text from the public domain Pfam and InterPro IPR002664

This article incorporates text from the public domain Pfam and InterPro IPR002663

This article incorporates text from the public domain Pfam and InterPro IPR004284

This article incorporates text from the public domain Pfam and InterPro IPR002662

This article incorporates text from the public domain Pfam and InterPro IPR007100

This virus-related article is a stub. You can help Wikipedia by expanding it.

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This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Birnavirus RNA dependent RNA polymerase (VP1) Provide feedback

Birnaviruses are dsRNA viruses. This family corresponds to the RNA dependent RNA polymerase. This protein is also known as VP1. All of the birnavirus VP1 proteins contain conserved RdRp motifs that reside in the catalytic "palm" domain of all classes of polymerases. However, the birnavirus RdRps lack the highly conserved Gly-Asp-Asp (GDD) sequence, a component of the proposed catalytic site of this enzyme family that exists in the conserved motif VI of the palm domain of other RdRps [1].

Literature references

Shwed PS, Dobos P, Cameron LA, Vakharia VN, Duncan R; , Virology 2002;296:241-250.: Birnavirus VP1 Proteins Form a Distinct Subgroup of RNA-Dependent RNA Polymerases Lacking a GDD Motif. PUBMED:12069523 EPMC:12069523

External database links

PANDIT:	PF04197
Pseudofam:	PF04197
SYSTERS:	Birna_RdRp

This tab holds annotation information from the InterPro database.

InterPro entry IPR007100

RNA-directed RNA polymerase (RdRp) (EC) is an essential protein encoded in the genomes of all RNA containing viruses with no DNA stage [PUBMED:2759231, PUBMED:8709232]. It catalyses synthesis of the RNA strand complementary to a given RNA template, but the precise molecular mechanism remains unclear. The postulated RNA replication process is a two-step mechanism. First, the initiation step of RNA synthesis begins at or near the 3' end of the RNA template by means of a primer-independent (de novo) mechanism. The de novo initiation consists in the addition of a nucleotide tri-phosphate (NTP) to the 3'-OH of the first initiating NTP. During the following so-called elongation phase, this nucleotidyl transfer reaction is repeated with subsequent NTPs to generate the complementary RNA product [PUBMED:11531403].

All the RNA-directed RNA polymerases, and many DNA-directed polymerases, employ a fold whose organisation has been likened to the shape of a right hand with three subdomains termed fingers, palm and thumb [PUBMED:9309225]. Only the catalytic palm subdomain, composed of a four-stranded antiparallel beta-sheet with two alpha-helices, is well conserved among all of these enzymes. In RdRp, the palm subdomain comprises three well conserved motifs (A, B and C). Motif A (D-x(4,5)-D) and motif C (GDD) are spatially juxtaposed; the Asp residues of these motifs are implied in the binding of Mg2+ and/or Mn2+. The Asn residue of motif B is involved in selection of ribonucleoside triphosphates over dNTPs and thus determines whether RNA is synthesised rather than DNA [PUBMED:10827187]. The domain organisation [PUBMED:9878607] and the 3D structure of the catalytic centre of a wide range of RdPp's, even those with a low overall sequence homology, are conserved. The catalytic centre is formed by several motifs containing a number of conserved amino acid residues.

There are 4 superfamilies of viruses that cover all RNA containing viruses with no DNA stage:

Viruses containing positive-strand RNA or double-strand RNA, except retroviruses and Birnaviridae: viral RNA-directed RNA polymerases including all positive-strand RNA viruses with no DNA stage, double-strand RNA viruses, and the Cystoviridae, Reoviridae, Hypoviridae, Partitiviridae, Totiviridae families.
Mononegavirales (negative-strand RNA viruses with non-segmented genomes).
Negative-strand RNA viruses with segmented genomes, i.e. Orthomyxoviruses (including influenza A, B, and C viruses, Thogotoviruses, and the infectious salmon anemia virus), Arenaviruses, Bunyaviruses, Hantaviruses, Nairoviruses, Phleboviruses, Tenuiviruses and Tospoviruses.
Birnaviridae family of dsRNA viruses.

The RNA-directed RNA polymerases in the first of the above superfamilies can be divided into the following three subgroups:

All positive-strand RNA eukaryotic viruses with no DNA stage.
All RNA-containing bacteriophages -there are two families of RNA-containing bacteriophages: Leviviridae (positive ssRNA phages) and Cystoviridae (dsRNA phages).
Reoviridae family of dsRNA viruses.

This family consists of the Birnaviridae enzymes. These proteins lack the highly conserved Gly-Asp-Asp (GDD) sequence, a component of the proposed catalytic site of this enzyme family that exists in the conserved motif VI of the palm domain of other RNA-directed RNA polymerases [PUBMED:12069523].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Molecular function	RNA-directed RNA polymerase activity (GO:0003968)
Biological process	viral genome replication (GO:0019079)

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.

Alignment types

We make a range of alignments for each Pfam-A family:

seed: the curated alignment from which the HMM for the family is built
full: the alignment generated by searching the sequence database using the HMM
RP15/RP35/RP55/RP75: Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
NCBI: alignment generated by searching the NCBI sequence database using the family HMM
meta: alignment generated by searching the metagenomics sequence database using the family HMM

Viewing

You can see the alignments as HTML or in three different sequence viewers:

jalview: a Java applet developed at the University of Dundee. You will need Java installed before running jalview
HTML: an HTML page showing the whole alignment.Please note: full Pfam alignments can be very large. These HTML views are extremely large and often cause problems for browsers. Please use either jalview or the Pfam viewer if you have trouble viewing the HTML version
PP/Heatmap: an HTML-based representation of the alignment, coloured according to the posterior-probability (PP) values from the HMM. As for the standard HTML view, heatmap alignments can also be very large and slow to render.
Pfam viewer: an HTML-based viewer that uses DAS to retrieve alignment fragments on request

Reformatting

You can download (or view in your browser) a text representation of a Pfam alignment in various formats:

Selex
Stockholm
FASTA
MSF

You can also change the order in which sequences are listed in the alignment, change how insertions are represented, alter the characters that are used to represent gaps in sequences and, finally, choose whether to download the alignment or to view it in your browser directly.

Downloading

You may find that large alignments cause problems for the viewers and the reformatting tool, so we also provide all alignments in Stockholm format. You can download either the plain text alignment, or a gzipped version of it.

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

	Seed (5)	Full (338)	Representative proteomes				NCBI (228)	Meta (0)
	Seed (5)	Full (338)	RP15 (0)	RP35 (0)	RP55 (0)	RP75 (0)	NCBI (228)	Meta (0)
Jalview	View	View					View
HTML	View	View
PP/heatmap	₁	View
Pfam viewer	View	View

¹Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: available, not generated, — not available.

Format an alignment

	Seed (5)	Full (338)	Representative proteomes				NCBI (228)	Meta (0)
	Seed (5)	Full (338)	RP15 (0)	RP35 (0)	RP55 (0)	RP75 (0)	NCBI (228)	Meta (0)
Alignment:
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

	Seed (5)	Full (338)	Representative proteomes				NCBI (228)	Meta (0)
	Seed (5)	Full (338)	RP15 (0)	RP35 (0)	RP55 (0)	RP75 (0)	NCBI (228)	Meta (0)
Raw Stockholm	Download	Download					Download
Gzipped	Download	Download					Download

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation

Seed source:

Pfam-B_2204 (release 7.3)

Previous IDs:

none

Type:

Family

Author:

Bateman A

Number in seed:

5

Number in full:

338

Average length of the domain:

401.50 aa

Average identity of full alignment:

68 %

Average coverage of the sequence by the domain:

97.83 %

HMM information

HMM build commands:

build method: hmmbuild -o /dev/null HMM SEED

search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	25.0	25.0
Trusted cut-off	33.3	30.8
Noise cut-off	17.2	17.1

Model length:

860

Family (HMM) version:

7

Download:

download the raw HMM for this family

Species distribution

Sunburst
Tree

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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.

How the sunburst is generated

The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, its distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.

In order to reduce the complexity of the representation, we reduce the number of taxonomic levels that we show. We consider only the following eight major taxonomic levels:

superkingdom
kingdom
phylum
class
order
family
genus
species

Colouring and labels

Segments of the tree are coloured approximately according to their superkingdom. For example, archeal branches are coloured with shades of orange, eukaryotes in shades of purple, etc. The colour assignments are shown under the sunburst controls. Where space allows, the name of the taxonomic level will be written on the arc itself.

As you move your mouse across the sunburst, the current node will be highlighted. In the top section of the controls panel we show a summary of the lineage of the currently highlighed node. If you pause over an arc, a tooltip will be shown, giving the name of the taxonomic level in the title and a summary of the number of sequences and species below that node in the tree.

Anomalies in the taxonomy tree

There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.

Missing taxonomic levels

Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.

Unmapped species names

The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.

So that these nodes are not simply omitted from the sunburst tree, we group them together in a separate branch (or segment of the sunburst tree). Since we cannot determine the lineage for these unmapped species, we show all levels between the superkingdom and the species as "uncategorised".

Sub-species

Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.

Too many species/sequences

For large species trees, you may see blank regions in the outer layers of the sunburst. These occur when there are large numbers of arcs to be drawn in a small space. If an arc is less than approximately one pixel wide, it will not be drawn and the space will be left blank. You may still be able to get some information about the species in that region by moving your mouse across the area, but since each arc will be very small, it will be difficult to accurately locate a particular species.

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Species trees

We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.

Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.

If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.

Interactive tree

For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.

We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.

Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.

We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.

You can use the tree controls to manipulate how the interactive tree is displayed:

show/hide the summary boxes
highlight species that are represented in the seed alignment
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Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Birna_RdRp domain has been found. There are 27 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

Loading structure mapping...

Archea	Eukaryota
Bacteria	Other sequences
Viruses	Unclassified
Viroids	Unclassified sequence

Family: Birna_RdRp (PF04197)

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Summary: Birnavirus RNA dependent RNA polymerase (VP1)

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Birnaviridae Edit Wikipedia article

Contents

[edit] Birnaviridae proteins

[edit] Viruses

[edit] References

[edit] External links

Birnavirus RNA dependent RNA polymerase (VP1) Provide feedback

Literature references

External database links

InterPro entry IPR007100

Gene Ontology

Domain organisation

Alignments

Alignment types

Viewing

Reformatting

Downloading

View options

Format an alignment

Download options

External links

HMM logo

Trees

Curation and family details

Curation

HMM information

Species distribution

Sunburst controls

Weight segments by...

Change the size of the sunburst

Colour assignments

Selections

Currently selected:

How the sunburst is generated

Colouring and labels

Anomalies in the taxonomy tree

Missing taxonomic levels

Unmapped species names

Sub-species

Too many species/sequences

Tree controls

Annotation

Download tree

Selected sequences

Species trees

Interactive tree

Structures