Extended Data Fig. 9: PNMA1 and PNMA4 form capsid-sized particles.
From: The retrotransposon-derived capsid genes PNMA1 and PNMA4 maintain reproductive capacity
(a, b) His-tagged PNMA1 (a) and PNMA4 (b) were expressed in E. coli and affinity purified on nickel resin. Imidazole elutions (15 ml) were concentrated and run over a Superose 6 (HiScale 80 ml) size exclusion column. Shown are UV absorbance traces of the run and Coomassie-stained SDS-PAGE of the fractions. The fractions used for TEM are noted in red. (c) Experimental setup: 3V5-tagged PNMA1, PNMA4, and ARC (control exported VLP) expression plasmids were transfected into HEK-293T cells. mCherry (control non-capsid) was co-expressed from the transfected plasmid. Cells were collected and lysed. Lysates were fractionated on 10–50% sucrose density gradients with continuous monitoring at 260 nm. (d) PNMA1, PNMA4, ARC (anti-V5), and mCherry protein levels in each fraction were analyzed by immunoblot. This experiment was repeated independently 3 times with similar results.
