title: Yingchengvirus
text: # Yingchengvirus
  
  Yingchengvirus is a genus of double stranded DNA viruses that infect haloarchaea. The genus was previously named Betasphaerolipovirus.
  
  ## Taxonomy
  
  The genus contains the following species:
  
  * Yingchengvirus HJIV1
  * Yingchengvirus NVIV1
  * Yingchengvirus SNJ1
  
  ## Morphology
  
  Viruses of this genus have tailless icosahedral virions with an internal lipid membrane located between the protein capsid and the circular double stranded DNA genome.
  
  ## Replication
  
  The temperate haloarchaeal virus SNJ1 displays lytic and lysogenic life cycles. During the lysogenic cycle, the virus resides in its host in the form of an extrachromosomal circular plasmid. Upon mitomycin C induction, large amounts of SNJ1 virions can be produced. SNJ1 genome replicates by the rolling-circle mechanism and is initiated by the virus-encoded RepA protein, which is homologous to the replication-initiation proteins of archaeal plasmids and bacterial transposases of the IS91 family insertion sequences. The virus is released by lysis of the infected cells.
  
  