Figure 2.

Expression of the pHes5-VNP reporter mimics Hes5-1 mRNA expression. (A-E) Following electroporation of pHes5-VNP, VNP mRNA can be detected only in the ventricular zone of the neural tube (C) similar to Hes5-1 mRNA (A) and is only detected in cells that also express Hes5-1 (D, E). In contrast, VNP mRNA expressed from pCAG-VNP is present not only in cells of the ventricular zone but also in the mantle layer (B). (F-I) VNP protein expression driven by pHes5-VNP is detected in cells that are mitotically active (H) or in S-phase, as detected by BrdU incorporation (I), similar to what is observed for Hes5-1 mRNA expression (F, G). Arrows in (E-I) identify cells co-labelled with the analysed markers. (J) Under conditions where low levels of reporter plasmids are electroporated (see Methods), VNP protein expressed from pHes5-VNP is restricted to neural progenitors, as virtually no co-expression with the HuC/D neuronal marker can be detected 24 h after electroporation. Dashed lines in (F-J) delineate the lumen of the neural tube.