Victoria Otto

Suche


B3 Interference of the viral effector proteins pp71 and IE1 with ND10-mediated intrinsic immunity against human cytomegalovirus infections

Principal investigator
Thomas Stamminger

Mentor
Manfred Marschall

Importance of SUMO interaction motifs for the ND10-antagonistic function of the human cytomegalovirus IE1 protein

Intrinsic antiviral resistance instituted by the subnuclear structure ND10 (nuclear domain 10) represents the first line of intracellular defense against human cytomegalovirus (HCMV) infections. The concerted action of the ND10-localized host restriction factors PML, hDaxx, ATRX and Sp100 leads to a repression of HCMV gene expression which is antagonized by viral effector proteins like IE1p72 (IE1) for efficient lytic replication. The IE1 protein of HCMV has the ability to compromise the posttranslational SUMO modification of PML and Sp100 which was proposed to result in a loss of ND10 integrity. However, the exact mode of action of how IE1 is capable of targeting ND10 for disruption still remains enigmatic. Thus, this project aims at a detailed characterization of the mechanism used by IE1 to disassemble and thereby counteract ND10.
Via in silico prediction four putative SUMO interaction motifs (SIMs) could be identified within the IE1 sequence. Interestingly, mutation of these SIMs by exchanging the respective amino acids to alanine did not only affect the ability of IE1 to abrogate the SUMO conjugation of PML and Sp100, but also IE1's capacity to disrupt ND10. In order to confirm the in vivo relevance of IE1 SIMs for HCMV replication, the focus of my work is to generate and characterize recombinant viruses harboring such mutations.

Figure:Immunofluorescence detection of PML and IE2 in primary human fibroblast cells depicts the capacity of IE2 to disrupt ND10 via de-SUMOylation of it´s major components 

 

Publications

 

Presentations

July 2012 4th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
Importance of SUMO interaction motifs for the ND10-antagonistic function of the human cytomegalovirus IE1 protein
Poster