Non-enveloped. Small, icosahedral, about 60 nm in size. A single molecule of circular dsDNA is contained within the T=7 icosahedral capsid, which is composed of 72 pentamers.


Circular dsDNA, about 8 kb in size, associated with cellular histones.
On rare non-specific recombination, the viral genome can be integrated in host chromosome. This inactivates the integrated virus but can gives the host cell a replicative advantage sometimes leading to malignant tumours.


Only one strand of the genome is transcribed and yield two classes of proteins expressed by alternative splicing :
a) Early Proteins: non-structural regulatory proteins (E1-E7).
b) Late Proteins: the structural proteins L1 and L2.



Replication is divided in two distinct steps that are linked to the differentiation state of the host epithelial cell:

a) The plasmid replication takes place in the basal squamous epithelial cells. It corresponds to viral DNA replication in synchrony with the host cell chromosome in order to ensures an average of one viral genome per basal cell.

  1. Attachment of the viral proteins to host receptors mediates endocytosis into vesicles in the basal squamous epithelial cell.
  2. Transport to the nucleus and uncoating of the viral DNA.
  3. Early-region transcription and translation of the early proteins.
  4. Steady-state viral DNA nuclear replication. Requires the origin of DNA replication in cis and the viral E1 and E2 proteins in trans.
b) The vegetative replication, which occurs in differentiated keratinocytes. In these cells, which no longer undergo cellular DNA synthesis, there is a burst of viral DNA synthesis with active production of virions.
  1. Vegetative viral DNA synthesis.
  2. Transcription of the late region.
  3. Capsid proteins L1 and L2 synthesis.
  4. Nuclear capsid assembly and release of viruses.

Matching UniProtKB/Swiss-Prot entries

32 entries grouped by strain (browse by keywords)

8 entries

Human papillomavirus type 4 reference strain

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VE1_HPV04Replication protein E1 (EC (ATP-dependent helicase E1)
VE2_HPV04Regulatory protein E2
VE4_HPV04Protein E4
VE6_HPV04Protein E6
VE7_HPV04Protein E7
VE8E2_HPV04Protein E8^E2C
VL1_HPV04Major capsid protein L1
VL2_HPV04Minor capsid protein L2

8 entries

Human papillomavirus type 65

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VE1_HPV65Replication protein E1 (EC (ATP-dependent helicase E1)
VE2_HPV65Regulatory protein E2
VE4_HPV65Protein E4
VE6_HPV65Protein E6
VE7_HPV65Protein E7
VE8E2_HPV65Protein E8^E2C
VL1_HPV65Major capsid protein L1
VL2_HPV65Minor capsid protein L2

6 entries

Human papillomavirus type 48

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VE1_HPV48Replication protein E1 (EC (ATP-dependent helicase E1)
VE2_HPV48Regulatory protein E2
VE6_HPV48Protein E6
VE7_HPV48Protein E7
VL1_HPV48Major capsid protein L1
VL2_HPV48Minor capsid protein L2

6 entries

Human papillomavirus type 60

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VE1_HPV60Replication protein E1 (EC (ATP-dependent helicase E1)
VE2_HPV60Regulatory protein E2
VE6_HPV60Protein E6
VE7_HPV60Protein E7
VL1_HPV60Major capsid protein L1
VL2_HPV60Minor capsid protein L2

4 entries

Human papillomavirus type 50

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VE2_HPV50Regulatory protein E2
VE7_HPV50Protein E7
VL1_HPV50Major capsid protein L1
VL2_HPV50Minor capsid protein L2