Co-dependence between trypanosome nuclear lamina components in nuclear stability and control of gene expression

TY - JOUR

T1 - Co-dependence between trypanosome nuclear lamina components in nuclear stability and control of gene expression

AU - Maishman, Luke

AU - Obado, Samson O.

AU - Alsford, Sam

AU - Bart, Jean

AU - Chen, Wei-Ming

AU - Ratushny, Alexander V.

AU - Navarro, Miguel

AU - Horn, David

AU - Aitchison, John D.

AU - Chait, Brian T.

AU - Rout, Michael P.

AU - Field, Mark C.

N1 - This work was supported by the Wellcome Trust (program grant 082813 to MCF, 093010 and 100320 to DH), the Gates Cambridge Trust (studentship to LM) and the NIH (R21 AI096069, U54 GM103511 to BTC, JA and MPR, U01 GM098256, P41 GM109824 to MPR, R01 GM112108 to JA and MPR, P50 GM076547 to JA and P41 GM103314 to BTC). Funding for open access charge: Wellcome Trust.

PY - 2016/12

Y1 - 2016/12

N2 - 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.

AB - 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.

KW - Trypanosoma brucei

KW - nuclear lamina

KW - epigenetics

KW - evolution

KW - gene expression

KW - heterochromatin

KW - VSG

U2 - 10.1093/nar/gkw751

DO - 10.1093/nar/gkw751

M3 - Article

C2 - 27625397

SN - 0305-1048

VL - 44

SP - 10554

EP - 10570

JO - Nucleic Acids Research

JF - Nucleic Acids Research

IS - 22

ER -