N⁶-methyladenosine mRNA marking promotes selective translation of regulons required for human erythropoiesis

Abstract

Many of the regulatory features governing erythrocyte specification, maturation, and associated disorders remain enigmatic. To identify new regulators of erythropoiesis, we performed a functional genomic screen for genes affecting expression of the erythroid marker CD235a/GYPA. Among validating hits were genes coding for the N 6 -methyladenosine (m 6 A) mRNA methyltransferase (MTase) complex, including, METTL14, METTL3, and WTAP. We found that m 6 A MTase activity promotes erythroid gene expression programs and lineage specification through selective translation of >200 m 6 A marked mRNAs, including those coding for SETD methyltransferase, ribosome, and polyA RNA binding proteins. Remarkably, loss of m 6 A marks resulted in dramatic loss of H3K4me3 across key erythroid-specific KLF1 transcriptional targets (e.g., Heme biosynthesis genes). Further, each m 6 A MTase subunit and a subset of their mRNAs targets, including BRD7, CXXC1, PABPC1, PABPC4, STK40, and TADA2B, were required for erythroid specification. Thus, m 6 A mRNA marks promote the translation of a network of genes required for human erythropoiesis.

Cytoplasmic mRNPs revisited: Singletons and condensates

“…[96,97] During human erythropoiesis, about 300 m 6 A-containing mRNAs were selectively translated, among which were found critical regulators of hematopoiesis and erythropoiesis. [98] This study suggests that m 6 and may be present in stress granules, thereby providing a mode of coordination. [99] Taken together, coordinated mRNA assembly in RNA regulons is an unlikely event in the case of pre-translational mRNPs.…”

“…[96,97] During human erythropoiesis, about 300 m 6 A-containing mRNAs were selectively translated, among which were found critical regulators of hematopoiesis and erythropoiesis. [98] This study suggests that m 6 A marks may promote expression of physiologically related mRNAs, but it does not provide evidence of the level of coordination. However, cytoplasmic YTH-domain proteins are able to undergo liquidliquid phase separation facilitated by polymethylated RNA in vitro and may be present in stress granules, thereby providing a mode of coordination.…”

The Untranslated Regions of mRNAs in Cancer

“…Both m 1 A and pseudouridine modifications change in response to cellular stresses such as heat shock and nutrient deprivation [105,136,139], indicating that these are dynamic marks on mRNA that could contribute to cancer pathogenesis. The advent of high-resolution mapping techniques coupled with genomic screening tools may provide a means to delineate their function in normal and disease states [104,105,107,135,136,[139][140][141].…”