The SUMOylation Pathway Restricts Gene Transduction by Adeno-Associated Viruses

PLoS Pathog. 2015 Dec 1;11(12):e1005281. doi: 10.1371/journal.ppat.1005281. eCollection 2015 Dec.


Adeno-associated viruses are members of the genus dependoviruses of the parvoviridae family. AAV vectors are considered promising vectors for gene therapy and genetic vaccination as they can be easily produced, are highly stable and non-pathogenic. Nevertheless, transduction of cells in vitro and in vivo by AAV in the absence of a helper virus is comparatively inefficient requiring high multiplicity of infection. Several bottlenecks for AAV transduction have previously been described, including release from endosomes, nuclear transport and conversion of the single stranded DNA into a double stranded molecule. We hypothesized that the bottlenecks in AAV transduction are, in part, due to the presence of host cell restriction factors acting directly or indirectly on the AAV-mediated gene transduction. In order to identify such factors we performed a whole genome siRNA screen which identified a number of putative genes interfering with AAV gene transduction. A number of factors, yielding the highest scores, were identified as members of the SUMOylation pathway. We identified Ubc9, the E2 conjugating enzyme as well as Sae1 and Sae2, enzymes responsible for activating E1, as factors involved in restricting AAV. The restriction effect, mediated by these factors, was validated and reproduced independently. Our data indicate that SUMOylation targets entry of AAV capsids and not downstream processes of uncoating, including DNA single strand conversion or DNA damage signaling. We suggest that transiently targeting SUMOylation will enhance application of AAV in vitro and in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Blotting, Western
  • Cell Line
  • Dependovirus / genetics*
  • Genetic Vectors / genetics*
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Molecular Sequence Data
  • RNA, Small Interfering / genetics
  • Sumoylation / genetics*
  • Transduction, Genetic*
  • Transfection


  • RNA, Small Interfering

Grants and funding

The Viro-Quant-CellNetworks RNAi Screening core facility represented by Holger Erfle and Lars Kaderali received funding within the Forsys-ViroQuant consortium (0313923) as well as by the Federal Ministry of Education and Research (BMBF) and the cluster of excellence, CellNetworks at Heidelberg University (EXC81). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.