Figure 5. Transient Isl1-Bound Enhancers Are Necessary for a Stable Expression of Motor Neuron Genes.
(A) Top: the location of Isl1-bound enhancers proximal to Hb9 gene in wild-type (WT) MNs. 629 bp genomic DNA of a nascent MN-specific Isl1-bound enhancer (Hb9-E1) and 847 bp of a maturing MN-specific Isl1-bound enhancer (Hb9-E5) were deleted using CRISPR genome editing (Ran et al., 2013). Bottom: Hb9 expression levels measured by quantitative RT-PCR in nascent and maturing MNs (normalized to WT expression levels of Hb9). Error bars represent SD, n = 4, two independent differentiations.
(B) Same as (A) except transient enhancers proximal to Isl1 gene (1,413 bp of the maturing MN-specific enhancer [Isl1-E3] and 1,519 bp of nascent MN-specific enhancer [Isl1-E4]) were deleted. Error bars represent SD. n = 4, two independent differentiations.
(C) ChIP-PCR analysis of Isl1 binding to maturing MN enhancers in an ESC line containing the deletion of a nascent MN-specific enhancer (Hb9-E1). Horizontal arrows mark the position of positive (blue; Pos) and negative (gray; Neg) PCR primer sets. Error bars represent SD, n = 3, two independent differentiations.
See also Figure S4.