Fig. 1. Characterization of the MBD¹ allele. (A) Overview indicating the exon-intron structure of the MBD2/3 locus and the position of the P element insertion. (B) Northern analysis of embryonic poly(A)⁺ RNA from 0- to 6-hour-old embryos. The upper panel shows significant levels of MBD2/3 mRNA in control (yw) embryos, while no signal was detectable in MBD¹ mutant embryos. A probe against the elongation factor EF148D was used as a loading control (lower panel). (C) Western analysis of 0-6 hours-old embryonic protein extracts. Nucleosome assembly protein 1 (NAP1) was used as loading control. (D) Confocal sections from embryos double immunostained with antibodies against MBD2/3 (green) and DNA (red). Mutant embryos showed only background levels for MBD2/3, while the DNA signal showed no quantitative differences between mutant and control.