PT - JOURNAL ARTICLE AU - Evgeny Sagulenko AU - Amanda Nouwens AU - Richard I. Webb AU - Kathryn Green AU - Benjamin Yee AU - Garry Morgan AU - Andrew Leis AU - Kuo-Chang Lee AU - Margaret K. Butler AU - Nicholas Chia AU - Uyen Thi Phuong Pham AU - Stinus Lindgreen AU - Ryan Catchpole AU - Anthony M. Poole AU - John A Fuerst TI - Nuclear pore-like structures in a compartmentalized bacterium AID - 10.1101/076430 DP - 2016 Jan 01 TA - bioRxiv PG - 076430 4099 - http://biorxiv.org/content/early/2016/09/21/076430.short 4100 - http://biorxiv.org/content/early/2016/09/21/076430.full AB - Planctomycetes are distinguished from other Bacteria by compartmentalization of cells via internal membranes, interpretation of which has been subject to recent debate regarding potential relations to Gram-negative cell structure. In our interpretation of the available data, the planctomycete Gemmata obscuriglobus contains a nuclear body compartment, and thus possesses a type of cell organization with parallels to the eukaryote nucleus. Here we show that pore-like structures occur in internal membranes of G.obscuriglobus and that they have elements structurally similar to eukaryote nuclear pores, including a basket, ring-spoke structure, and eight-fold rotational symmetry. Bioinformatic analysis of proteomic data reveals that some of the G. obscuriglobus proteins associated with pore-containing membranes possess structural domains found in eukaryote nuclear pore complexes. Moreover, immuno-gold labelling demonstrates localization of one such protein, containing a β-propeller domain, specifically to the G. obscuriglobus pore-like structures. Finding bacterial pores within internal cell membranes and with structural similarities to eukaryote nuclear pore complexes raises the dual possibilities of either hitherto undetected homology or stunning evolutionary convergence.