MBNL3 and myotonic dystrophy type 1: To more generally examine the role of Mbnl338kD depletion in the development of DM1 like splice errors we studied a range of splice events in the heart, skeletal muscle and lens of adult Mbnl3+/+ and Mbnl3ΔE2 mice and E18 Mbnl3+/+ embryos.