GSE161763
CblX disease is both an inborn error of cobalamin metabolism and a ribosomopathy
CblX is a recently described X-linked variant of combined methylmalonic acidemia and homocystinuria, cblC type, which is the most common inborn error of intracellular cobalamin metabolism. While cblC is due to mutations in MMACHC, which is in the cobalamin metabolic pathway, cblX is caused by mutations in the transcriptional cofactor HCFC1 and its obligate transcription factor partner RONIN . Since HCFC1 and RONIN jointly regulate MMACHC transcription, cblX patients suffer from low levels of MMACHC during development and thus develop a disease highly similar to cblC. Beyond this finding, there is little else known about the other genes de-regulated in cblX and the resulting pathophysiology. Therefore, we have generated the first mouse models of this disease (Hcfc1A115V/Y and RoninF80L/F80L). We show that our cblX models exhibit the expected metabolic perturbations, along with CNS, hematopoietic and cardiac developmental defects, typically observed in cblC patients. We also uncovered a large cohort of target genes that encode ribosome protein subunits as well as unexpected phenotypes that we ascribe to deregulation of ribosome biogenesis impacting normal translation during development. In addition to identifying RONIN and HCFC1 as new transcriptional regulators of ribosome biogenesis, we establish cblX as a complex syndrome exhibiting aspects of cblC and a ribosomopathy. Overall design: RNA was extracted from the brains of control and mutant Ronin (F80L/F80L) animals for RNA-seq library preparation. And the brains of control animals were used as input for Ronin ChIP-seq.