ZC3HC1 has functions distinct from TPR and is dispensable for TPR localisation to the nuclear basket

Abstract

Background: The nuclear basket is a "fishtrap"-like structure on the nucleoplasmic face of the nuclear pore complex which has been implicated in diverse functions including RNA export, heterochromatin organisation, and mitosis. Recently, a novel component of the nuclear basket, ZC3HC1, has been described. The localisation of ZC3HC1 to nuclear pores has been reported to occur reciprocally with TPR, a major structural component of the nuclear basket. Methods: Using siRNA-mediated knock down, immunofluorescence and RNA sequencing we compare the consequences of depleting two proteins of the nuclear pore basket - TPR and ZC3HC1. Results: We show that in human fibroblasts, although ZC3HC1 localisation to nuclear pores is TPR-dependent, TPR localises to pores regardless of the presence of ZC3HC1. We demonstrate that knockdown of TPR and ZC3HC1 produce distinct transcriptional profiles. Conclusions: Our results suggest that there is little overlap in function between these two nuclear basket proteins in human diploid fibroblasts.