Fig. 1

KIF20A, RGS3, and Gα subunit are present in the ICB of mitotic NPCs a RNA in situ hybridization revealed KIF20A mRNA in the germinal zone of the cortex where progenitor cells reside, similar to the transcripts of RGS3 and ephrin-B1 observed previously. ctx: cortex, ge: ganglionic eminence, SVZ: subventricular zone, VZ: ventricular zone. b Anti-KIF20A staining showed that KIF20A protein is more strongly expressed in apically localized mitotic cells. Scale bar represents 100 μm. c Expression of an RFP-KIF20A fusion protein in the cortex revealed its pattern in the presumptive intercellular bridge of apically dividing cells. Scale bar represents 100 μm. d En-face view of a whole-mount anti-KIF20A staining with E14.5 cortices revealed that KIF20A was present on the ventricular surface. Scale bar represents 100 μm. e In dissociated primary cortical progenitor cells with lentiviral expression of a mCherry-tagged RGS3 fusion protein, mCherry-RGS3 could be found in the midbody area of telophase cells with endogenous KIF20A. Scale bar represents 10 μm. f Immunostaining showed that Gαo2 could also be seen present at the midbody region of dividing cortical progenitor cells. Scale bar represents 10 μm. g Cells from the E14.5 mouse cortices were cultured for 20 h and stained for KIF20A, Ki67, and β-III-tubulin. Paired cells showing symmetric progenitor–progenitor self-renewal (P–P), asymmetric progenitor–neuron (P–N) differentiation, or symmetric neuron-neuron (N–N) differentiation were documented. KIF20A expression was selectively associated with daughter progenitor cells. Scale bar represents 10 μm. h Cortical cells electroporated with a plasmid carrying a CAG promoter-RFP-KIF20A cassette and a DCX promoter-GFP cassette were analyzed after 20 h in culture. In paired cells (showing three examples) with asymmetrical division (with daughter neurons marked by GFP), RFP-KIF20A, and GFP showed complementary patterns of expression. Scale bar represents 10 μm