A Point Mutation in the RNA Recognition Motif of CSTF2 Associated with Intellectual Disability in Humans Causes Defects in 3' End Processing [3'prime-seq]
CSTF2 encodes an RNA-binding protein that is essential for mRNA cleavage and polyadenylation (C/P). No disease-associated mutations have been described for this gene. Here, we report a mutation in the RNA recognition motif (RRM) of CSTF2 that changes an aspartic acid at position 50 to alanine (p.D50A), resulting in intellectual disability in male patients. In mice, this mutation was sufficient to alter polyadenylation sites in over 1,300 genes critical for brain development. Using a reporter gene assay, we demonstrated that C/P efficiency of CSTF2D50A was lower than wild type. To account for this, we determined that p.D50A changed locations of amino acid side chains altering RNA binding sites in the RRM. The changes modified the electrostatic potential of the RRM leading to a greater affinity for RNA. These results highlight the significance of 3' end mRNA processing in expression of genes important for brain plasticity and neuronal development. Overall design: Total brain RNA from three wild type and five Cstf2 mutant mice at 50 days were subjected to RNA-seq using the Illumina protocol Please note the column headers in the processed data files represent: *_pA1 (polyadenylation site 1): the proximal cleavage and polyadenylation site, which is closer to the transcription start site in a gene. *_pA2 (polyadenylation site 2):the distal cleavage and polyadenylation site, which is further to the transcription start site in a gene. *_exon3 (3' most exon): the most distal cleavage and polyadenylation site in the 3' most exon. *_UPS (upstream exon): the proximal cleavage and polyadenylation site, which is in an upstream (closer to the transcription start site) exon of the 3' most exon. Use of one (exon3) or the other (UPS) cleavage and polyadenylation site often produces mRNAs that differ in their ORFs specifically in the carboxy-end of the protein.