RNA binding protein-mediated post-transcriptional gene regulation in medulloblastoma

Abstract

Medulloblastoma, the most common malignant brain tumor in children, is a disease whose mechanisms are now beginning to be uncovered by high-throughput studies of somatic mutations, mRNA expression patterns, and epigenetic profiles of patient tumors. One emerging theme from studies that sequenced the tumor genomes of large cohorts of medulloblastoma patients is frequent mutation of RNA binding proteins. Proteins which bind multiple RNA targets can act as master regulators of gene expression at the post-transcriptional level to co-ordinate cellular processes and alter the phenotype of the cell. Identification of the target genes of RNA binding proteins may highlight essential pathways of medulloblastomagenesis that cannot be detected by study of transcriptomics alone. Furthermore, a subset of RNA binding proteins are attractive drug targets. For example, compounds that are under development as anti-viral targets due to their ability to inhibit RNA helicases could also be tested in novel approaches to medulloblastoma therapy by targeting key RNA binding proteins. In this review, we discuss a number of RNA binding proteins, including Musashi1 (MSI1), DEAD (Asp-Glu-Ala-Asp) box helicase 3 X-linked (DDX3X), DDX31, and cell division cycle and apoptosis regulator 1 (CCAR1), which play potentially critical roles in the growth and/or maintenance of medulloblastoma.

Fig. 1

Domain structures of selected RNA binding proteins. Vertical lines above the protein represent point mutations identified in medulloblastoma sequencing studies (Jones et al., 2012; Pugh et al., 2012; Robinson et al., 2012). Red lines = residues with mutations identified in multiple tumors. X = truncating mutation. RRM = RNA recognition motif, DEAD = DEAD/DEAH box RNA helicase domain, Hel_C = helicase C domain, S1L = S1-like RNA binding domain, DBC1 = domain found in DBC1, SAP = SAF-A/B, Acinus and PIAS DNA/RNA binding motif. Domain annotation as predicted by InterPro (Hunter et al., 2012).