Backbone 1HN, 13C, and 15N resonance assignments of the tandem RNA-binding domains of human DGCR8

Abstract

Double-stranded RNA binding domain (dsRBD) containing proteins are critical components of the microRNA (miRNA) pathway, with key roles in small RNA biogenesis, modification, and regulation. DiGeorge Critical Region 8 (DGCR8) is a 773 amino acid, dsRBD-containing protein that was originally identified in humans as a protein encoded in the region of chromosome 22 that is deleted in patients with DiGeorge syndrome. Now, it is realized that DGCR8 complements the nuclear RNase III Drosha to initiate miRNA biogenesis by promoting efficient recognition and cleavage of primary miRNAs (pri-miRNA). A pair of C-terminal tandem dsRBDs separated by a flexible linker are required for pri-miRNA substrate binding and recognition. The crystal structure of the DGCR8 core region comprising residues 493-720 revealed that each dsRBD adopts the canonical αβββα fold. However, several residues located in important flexible regions including the β1-β2-loop implicated in canonical dsRNA recognition are absent in the crystal structure and no RNA-bound structure of DGCR8 has been reported. Here we report the (1)H(N), (13)C, and (15)N backbone resonance assignments of the 24 kDa, 214 amino acid human DGCR8(core) (residues 493-706) by heteronuclear NMR spectroscopy. Our assignments lay the foundation for a detailed solution state characterization of the dynamical and RNA-binding properties of this protein in solution.