Figure 5. Expression of ARHGAP36 in the developing spinal MNs.

(A) Induction of ARHGAP36 expression in MNs differentiated from mouse ESCs was determined by qRT-PCR. Relative expression levels are shown as the mean of duplicate values obtained from representative experiments. Error bars represent standard deviation. (B,C) ARHGAP36 was specifically expressed in MNs of mouse embryos at E9.5, E10.5, E11.5 and E12.5 stages, as shown by ISH with a probe detecting ARHGAP36 and IHC for ARHGAP36, Isl1/FoxP1, Isl1/Hb9, Lhx3/Hb9 and FoxP1. From E12.5 and onward, ARHGAP36 expression was highly enriched in LMCl (Isl1^-/FoxP1⁺) region, some in MMC-rhomboideus (Rb) (Hb9⁺/Lhx3^low) and a very little in the most medial part of MMC but not in LMCm (Isl1⁺/FoxP1⁺) at cervical level. ARHGAP36 is also expressed in PGC (FoxP1⁺/Isl1⁺) and HMC (Isl1⁺/Hb9⁺) neurons at thoracic level but with relatively lower expression compared to the cervical level. At lumbar level, ARHGAP36 is enriched in LMCl (Isl1^-/FoxP1⁺) of the spinal cord. Scale bars: 100 μm. (D) Co-localization of ARHGAP36 with Shh shown by ISH of Shh and IHC of ARHGAP36 in mouse E12.5 spinal cord at cervical level. Shh is co-localized with ARHGAP36 mostly in LMCl region in mouse spinal cord. Scale bars: 100 μm. (E) Schematic drawing shows the LMCm, LMCl, HMC, MMC and MMC-rhomboideus (Rb) motor columns in the ventral spinal cord with representative markers.