The nuclear lamina supports many functions, including maintaining nuclear structure and gene expression control and correct spatio-temporal assembly is vital to meet these activities. Recently, multiple lamina systems have been described that, despite independent evolutionary origins, share analogous functions. In trypanosomatids the two known lamina proteins, NUP-1 and NUP-2, have molecular masses of 450 and 170 kDa respectively, which demands a distinct architecture from the ~60 kDa lamin-based system of metazoa and other lineages. To uncover organisational principles for the trypanosome lamina we generated NUP-1 deletion mutants to identify domains and their arrangements responsible for oligomerisation. Both N- and Ctermini act as interaction hubs and perturbation of these interactions impacts additional components of the lamina and nuclear envelope. Further, the assembly of NUP-1 terminal domains suggests intrinsic organisational capacity. Remarkably, there is little impact on silencing of telomeric variant surface glycoprotein genes. We suggest that both terminal domains of NUP-1 have roles in assembling the trypanosome lamina and propose a novel architecture based on a hub and spoke configuration.
- macromolecular assembly
- nuclear organisation