Isolation and validation of Drosophila embryo MARs. (A) Overview of MAR DNA isolation procedure. (B) Size distribution of MAR DNA after electrophoresis on 1.2% agarose gel. M-Molecular weight marker; Lane 1-Genomic DNA; Lane 2-MAR DNA; Lane 3-MAR DNA + DNaseI; Lane 4-MAR DNA + RNaseA. (C) Slot-blot hybridization to show enrichment of known MARs in the MAR DNA preparation. Equal quantity of plasmids (1 μg) carrying sequences of BEAF protein exon as –ve control (slot i), MAR at histone gene locus (slot ii) and scs’ MAR at Hsp70 locus (slot iii) were loaded in each slot. Genomic DNA and MAR DNA were 32P labelled by random primer labelling method and used for hybridization of the upper and the lower panel respectively. (D) Southern validation for 21 MARs and 8 non-MAR regions chosen on the basis of sequencing data. The upper panel shows the EtBr stained gel profile of the PCR amplified fragments and lower panel shows the blot probed with 32P labelled MAR DNA.