Co-dependence between trypanosome nuclear lamina components in nuclear stability and control of gene expression.
The nuclear lamina is a filamentous structure subtending the nuclear envelope and required for chromatin organization, transcriptional regulation and maintaining nuclear structure. The trypanosomatid coiled-coil NUP-1 protein is a lamina component functionally analogous to lamins, the major lamina proteins of metazoa. There is little evidence for shared ancestry, suggesting the presence of a distinct lamina system in trypanosomes. To find additional trypanosomatid lamina components we identified NUP-1 interacting proteins by affinity capture and mass-spectrometry. Multiple components of the nuclear pore complex (NPC) and a second coiled-coil protein, which we termed NUP-2, were found. NUP-2 has a punctate distribution at the nuclear periphery throughout the cell cycle and is in close proximity to NUP-1, the NPCs and telomeric chromosomal regions. RNAi-mediated silencing of NUP-2 leads to severe proliferation defects, gross alterations to nuclear structure, chromosomal organization and nuclear envelope architecture. Further, transcription is altered at telomere-proximal variant surface glycoprotein (VSG) expression sites (ESs), suggesting a role in controlling ES expression, although NUP-2 silencing does not increase VSG switching. Transcriptome analysis suggests specific alterations to Pol I-dependent transcription. NUP-1 is mislocalized in NUP-2 knockdown cells and vice versa, implying that NUP-1 and NUP-2 form a co-dependent network and identifying NUP-2 as a second trypanosomatid nuclear lamina component.
School of Life Sciences, University of Dundee, Dundee, Scotland, DD1 5EH, UK.
Luke
L
Maishman
The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Samson O
SO
Obado
London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Sam
0000-0001-8621-4920
S
Alsford
Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Cientificas, 18100 Grenada, Spain.
Jean-Mathieu
JM
Bart
Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA.
Wei-Ming
WM
Chen
Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA.|Institute for Systems Biology, Seattle, WA 98109, USA.
Alexander V
AV
Ratushny
Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Cientificas, 18100 Grenada, Spain.
Miguel
M
Navarro
School of Life Sciences, University of Dundee, Dundee, Scotland, DD1 5EH, UK.
David
D
Horn
Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA.|Institute for Systems Biology, Seattle, WA 98109, USA.
John D
JD
Aitchison
The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Brian T
BT
Chait
The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Michael P
MP
Rout
School of Life Sciences, University of Dundee, Dundee, Scotland, DD1 5EH, UK mfield@mac.com.
Mark C
0000-0002-4866-2885
MC
Field
D002875:Chromosomes / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D005786:Gene Expression Regulation; D034881:Nuclear Lamina / Q000502:physiology* / Q000648:ultrastructure; D022022:Nuclear Pore / Q000378:metabolism / Q000648:ultrastructure; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D059467:Transcriptome; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure
D028861:Nuclear Pore Complex Proteins; D015800:Protozoan Proteins