Characterization and crystallization of human DPY-30-like protein, an essential component of dosage compensation complex.

Human DPY-30-like is a homolog of C. elegans DPY-30. DPY-30 is an essential component of dosage compensation machinery and loss of dpy-30 activity results in XX-specific lethality. In XO animals, DPY-30 is required for developmental processes other than dosage compensation. In yeast, the homolog of DPY-30, Saf19p, functions as a member of histone 3 lysine 4 methylation complex, which is the key part of epigenetic developmental control. In this report, human DPY-30-like protein was overexpressed and purified with the goal of structure determination. It was crystallized at 291 K in hanging drops by the vapour diffusion technique from a precipitant solution consisting of (NH4)2SO4 (1.5-2.0 M), Tris-HCl (0.1 M, pH 8.0). The crystal diffracted to 2.7 A resolution at 100 K in-house and belongs to the space group P4(1)2(1)2 or P4(3)2(1)2 with unit-cell parameters of a=b=74.5 A, c=87.0 A, alpha=beta=gamma=90.0 degrees. The asymmetric unit contains two molecules with 49% solvent content. We also analyzed its biochemical and biophysical characterizations. Efforts are now under way to determine the molecular structure of the DPY-30-like. These studies will open a new avenue towards the structure-based functional analysis of human DPY-30-like and dosage compensation machinery.