Supplementary material for Greally et al. (1999) Proc. Natl. Acad. Sci. USA 96 (25), 14430-14435.
Fig. 6.
Nuclear matrix binding assays (NMBAs) of the human imprinting center (IC)/small nuclear riboprotein (SNRPN) upstream reading frame (SNURF-SNRPN) region were performed on an EcoRI digestion of l48.8, EcoRI-BamHI digestion of l48.29, l48.33, and L48.3I, BamHI-BglII digestion of 8-1-1 and EcoRI-XbaI digestion of 12-E-E. The positive bands are identified by arrowheads and size, allowing their correlation with position within each genomic clone (also marked). For example, the 6.5-kb fragment from l48.29 and L48.3I and the 4.4-kb fragment from l48.8 are all from the same region and are consistently positive in all three assays. Although the smallest bands from 8-1-1 and the second largest band from 12-E-E appear marginally more intense than the plasmid control, the densitometric measurement of these relative intensities showed this difference to be minimal, less than those we previously observed for matrix attachment regions (MARs) from the Ins2/H19 region [Greally, J. M., Guinness, M. E., McGrath, J. & Zemel, S. (1997) Mamm. Genome 8, 805-810] and the Igk MAR positive control probe, so these restriction fragments are scored as negative. The smaller restriction fragments from 12-E-E are not labeled individually on the map, because they are all positive. In total, 49.1 kb of the 68.9-kb region is biochemically defined as MARs by using the NMBA at the IC/SNURF-SNRPN region.