Figure 5.

The NMTS is sufficient to direct a heterologous nuclear protein to the nuclear matrix. (A) In situ immunofluorescence analysis of nuclear matrices prepared from ROS 17/2.8 cells transfected with expression vectors for GAL4-(1–147), GAL4-(1–147)/AML171–480, GAL4/AML351–381, and GAL4/AML432–480 as indicated. Fusion proteins were visualized using a GAL4-specific primary antibody and a fluorescein isothiocyanate-conjugated secondary antibody. (Bar = 10 μm.) (B) Comparison of the amino acid sequence of the AML-1B NMTS with sequences of other members of the AML family, including the bone-related AML-3 factor (62, 63). Three motifs (boxes A, B, and C) show conservation of amino acids with either aliphatic (•), aromatic (○), aliphatic hydroxyl (▿), or basic (+) side chains. The brackets denote segments with a propensity to form turns or a preponderance of hydrophobic or hydrophilic residues, based on the Kyte–Doolittle hydropathy plot using Genetics Computer Group (Madison, WI) software. The NMTS is devoid of negatively charged amino acids; 20 of 31 amino acids are G, A, Y, T, or S.