# Differentiation of Expectation w.r.t distribution

I was looking into Coordinate Ascent Variational Inference formula and came across a step where we need to find the argmax of q($$z_j$$) for the equation given below. I am not sure how the differentiation of the expected value w.r.t the distribution happens here.

$$\frac{d}{dq(z_j)} [\int q(z_j) E_{q_{-j}}[log(p(z_j|z_{-j}, x))]dz_j] = E_{q_{-j}}[log(p(z_j|z_{-j}, x))]$$