RNA-Binding Proteins PCBP1 and PCBP2 Are Critical Determinants of Murine Erythropoiesis

ABSTRACT

We previously demonstrated that the two paralogous RNA-binding proteins PCBP1 and PCBP2 are individually essential for mouse development: Pcbp1-null embryos are peri-implantation lethal, while Pcbp2-null embryos lose viability at midgestation. Midgestation Pcbp2^−/− embryos revealed a complex phenotype that included loss of certain hematopoietic determinants. Whether PCBP2 directly contributes to erythropoietic differentiation and whether PCBP1 has a role in this process remained undetermined. Here, we selectively inactivated the genes encoding these two RNA-binding proteins during differentiation of the erythroid lineage in the developing mouse embryo. Individual inactivation of either locus failed to impact viability or blood formation. However, combined inactivation of the two loci resulted in midgestational repression of erythroid/hematopoietic gene expression, loss of blood formation, and fetal demise. Orthogonal ex vivo analyses of primary erythroid progenitors selectively depleted of these two RNA-binding proteins revealed that they mediate a combination of overlapping and isoform-specific impacts on hematopoietic lineage transcriptome, impacting both mRNA representation and exon splicing. These data lead us to conclude that PCBP1 and PCBP2 mediate functions critical to differentiation of the erythroid lineage.

KEYWORDS:

• murine erythropoiesis
• posttranscriptional controls
• PCBP1
• PCBP2
• RNA-binding proteins
• conditional gene inactivation

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SUPPLEMENTAL MATERIAL

Supplemental material is available online only.

ACKNOWLEDGMENTS

The authors appreciate the generosity of Liebhaber laboratory members for sharing various reagents and thoughts. We thank Daphne Yang, and Gayatri M. Schur for their help with several of the experiments.

This work was supported by a National Institutes of Health grant (MERIT grant R01HL065449 to S.A.L.). The work of Y.B. and A.J. was supported by grant R01GM128096 to Y.B.

X.J. and S.A.L. conceptualized the study, designed the experiments, and supervised the study. X.J., J.H., L.R.G., A.K., and C.D.-L. performed the experiments. E.T. aided in isolation of hematopoietic progenitors under the supervision of M.J.W. A.J. performed the bioinformatics analysis under the supervision of Y.B. X.J., A.J., and S.A.L. wrote the paper.

We declare that we have no conflicts of interest.