UAS regulatory sequences drive expression of the B isoform of sr.
embryonic somatic muscle cell, with Scer\GAL469B
Expression of srB.Scer\UAS under the control of Scer\GAL469B causes defects in somatic muscle pattern in embryos. However, unlike overexpression of the A isoform, expression of this B isoform does not affect germ band retraction or cell shape.