The putative zinc finger of a caulimovirus is essential for infectivity but does not influence gene expression. Academic Article uri icon

abstract

  • Plant pararetroviruses, such as caulimoviruses, and animal retroviruses have in common the presence of a highly conserved arrangement of cysteines and a histidine in the precursor of the capsid protein. The composition of these amino acids resembles a zinc finger element, a structure that is common to a class of eukaryotic proteins that regulate gene expression. The role of the putative zinc finger in the life-cycle of caulimoviruses was investigated by introducing specific mutations in the coat protein coding region of a cloned and infectious form of figwort mosaic virus, a caulimovirus. This mutated viral genome, which no longer encoded the conserved cysteine and histidine residues, was not infectious in plants. Transient expression assays in protoplasts showed that expression of a reporter gene inserted at different places in the genome was not detectably influenced by the coat protein or its putative zinc finger. It appears that the zinc finger-like element of caulimoviruses is not involved in the regulation of gene expression. These observations support a model which predicts a function of the zinc finger in specific recognition and packaging of viral RNA into virions prior to reverse transcription.

published proceedings

  • J Gen Virol

author list (cited authors)

  • Scholthof, H. B., Wu, F. C., Kiernan, J. M., & Shepherd, R. J.

citation count

  • 9

complete list of authors

  • Scholthof, HB||Wu, FC||Kiernan, JM||Shepherd, RJ

publication date

  • April 1993