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Uukuvirus (taxid:2734594)

VIRION

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Enveloped, spherical. Diameter from 80 to 120nm. Glycoproteins at the surface of the envelope are arranged on an icosahedral lattice, with T=12 symmetry.

GENOME

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Segmented Negative-stranded RNA linear genome, L segment is about 6.5kb, M segment about 3.2kb and S segment about 1.7kb.
Some viruses genome comprise only Sand L segments. Encodes for two to 4 proteins.

GENE EXPRESSION

Transcription starts by viral RNA dependent RNA polymerase (L) binding to a promoter on each encapsidated segment, and is terminated by a strong hairpin sequence at the end of each gene. These are capped by L protein during synthesis using cap snatching , but are not polyadenylated.
S segment uses ambisense strategy to encode for several proteins: both genomic and antigenomic RNA are transcribed. The hairpin sequence is a stop polymerase signal which prevents ambisense transcription from producing dsRNA.

ENZYMES

REPLICATION

CYTOPLASMIC

  1. Virus attaches to host receptors though Gn-Gc glycoprotein dimer, and is endocytosed into vesicles in the host cell.
  2. Fusion of virus membrane with the vesicle membrane; ribonucleocapsid segments are released in the cytoplasm.
  3. Transcription, viral mRNAs are capped in the cytoplasm.
  4. Replication presumably starts when enough nucleoprotein is present to encapsidate neo-synthetized antigenomes and genomes.
  5. The ribonucleocapsids buds at Golgi apparatus, releasing the virion by exocytosis.
These structures were created with the help of Colabfold by Jason Nomburg, Nathan Price and Jennifer Doudna (ModelArchive).

Huangpi Tick Virus 2 taxid:1608048

Protein ModelArchive
Envelopment polyprotein (M polyprotein) ma-jd-viral-66159
Nonstructural protein ma-jd-viral-25063
Nucleoprotein ma-jd-viral-17382