Fig. 1. SCP3 accumulates on the LEs during late diplotene, is partially lost from LEs during diakinesis, but still persists at centromeres and arms in prometaphase I bivalents. SCP3 is labelled in green; Rad21 in red in B,E; centromeres in red in G,H,K,M,N, and DNA in blue. (A-C) Superimposition of five focal planes throughout a pachytene spermatocyte showing colocalization of SCP3 and Rad21 at SCs. (D-F) Superimposition of nine focal planes throughout an early diplotene spermatocyte showing colocalization of SCP3 and Rad21 at desynapsed LEs. (G-I) Partial projections from different focal planes throughout a late diplotene nucleus where some accumulations of SCP3 (red arrowheads) are found on some desynapsed LEs. Some small SCP3 agglomerates (white arrowhead in H) are also observed separated from LEs. The sex AEs are indicated (XY). The inset in G is a magnification of the boxed area showing the SCP3 labelling at an homologous centromere. (J) Superimposition of different focal planes throughout an early diakinesis nucleus where a large number of SCP3 accumulations (red arrowheads) are observed along thin desynapsed LEs (white arrows). Some SCP3 agglomerates (white arrowheads) are detected in the nucleoplasm. (K,L) Single focal plane throughout a late diakinesis nucleus showing a high SCP3 labelling dispersed in the nucleoplasm where some large SCP3 agglomerates (white arrowheads) are present. An SCP3 accumulation (red arrowhead) is observed in continuity with a thin desynapsed LE (white arrows). The inset in K is a magnification of the boxed area showing the SCP3 labelling at a homologous centromere. The inset in L shows three SCP3 accumulations along unsynapsed sex AEs. (M,N) Two focal planes of a prometaphase I spermatocyte. The nucleoplasm shows a faint labelling and some large SCP3 agglomerates (arrowheads). SCP3 persists at centromeres and appears as wiggly lines (arrows) inside bivalents. The inset in M is a magnification of the boxed area showing the SCP3 labelling at a homologous centromere. Scale bar: 10 µm.