Figure 3. Dux, but not DUX4, activates transcription of repetitive elements characteristic of the early embryo in mouse muscle cells.

(a) Expression levels of repeats during Dux expression in mouse cells compared to un-induced cells of the same cell line, broken down by repeat class. For LTR elements broken down by family, see Supplementary Figure 6a–c. Each dot is a repeatName as defined by RepeatMasker. Red color indicates differential expression at absolute(log2-Foldchange)>=1 and adjusted p-value<=0.05. Number in parentheses is log2-FoldChange.

(b) Same as (a) for DUX4-expressing mouse muscle cells compared to un-induced cells of the same cell line.

(c) Same as (a) for DUX4-expressing human muscle cells compared to un-induced cells of the same cell line, data previously published¹⁸.

(d) Example of a Dux ChIP-seq peak in MERV-L (MT2-element in RepBase nomenclature). Track height is 200 reads for all tracks. mm10 genome location is chr15:52,742,953–52,744,319.

(e) Luciferase assay comparing the activation of a 2C-active MERV-L element reporter by either Dux, DUX4 or an empty vector. The MERV-L element contains a match to the Dux motif and was mutated as shown in cartoon to the right and the full sequence is in Supplementary Figure 6d. Activation of the mutated MERV-L reporter is also shown.

Data shown are mean fold change over empty vector of 3 cell cultures prepared in parallel for each condition. Error bars are s.e.m. The non-mutated MERV-L reporter activation experiment was repeated on three separate occasions with consistent results. The mutated MERV-L reporter experiment was performed on one occasion.