FIG. 1.

Expression of MrgX mRNA and protein. (A) MrgX mRNA expression in adult tissues and embryos. A mouse RNA Master Blot was hybridized using an MrgX-specific probe. (B) MrgX and Mrg15 mRNA expression during mouse development. MrgX and Mrg15 mRNA expression in embryos and embryonic tissues was determined by Northern blotting. EtBr staining of RNAs (28S and 18S) indicated an equal amount of loading of the various samples. (C) Subnuclear fractionation analysis of MRGX and MRG15 proteins in HeLa cells. Nuclear proteins from HeLa cells were fractionated as reported previously (31). The amount of sample loaded in each lane was based on cell number (protein from 5 × 10⁵ cells per lane). MRGX and MRG15 proteins were detected by Western blotting. The presence of lamins A and C served as a marker for the nuclear matrix fraction. Lanes: 1, 0.25 M (NH₄)₂SO₄ extracted fraction after DNase I treatment; 2, 2 M NaCl extracted fraction; 3, extracted fraction after RNase A plus RNase T1 treatment; 4, nuclear matrix (pelleted) fraction.