Ribonuclease inhibitor 1 regulates erythropoiesis by controlling GATA1 translation
Vijaykumar Chennupati, … , Trang Hoang, Ramanjaneyulu Allam
Vijaykumar Chennupati, … , Trang Hoang, Ramanjaneyulu Allam
Published February 6, 2018
Citation Information: J Clin Invest. 2018;128(4):1597-1614. https://doi.org/10.1172/JCI94956.
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Research Article Development Hematology Article has an altmetric score of 5

Ribonuclease inhibitor 1 regulates erythropoiesis by controlling GATA1 translation

Abstract

Ribosomal proteins (RP) regulate specific gene expression by selectively translating subsets of mRNAs. Indeed, in Diamond-Blackfan anemia and 5q– syndrome, mutations in RP genes lead to a specific defect in erythroid gene translation and cause anemia. Little is known about the molecular mechanisms of selective mRNA translation and involvement of ribosomal-associated factors in this process. Ribonuclease inhibitor 1 (RNH1) is a ubiquitously expressed protein that binds to and inhibits pancreatic-type ribonucleases. Here, we report that RNH1 binds to ribosomes and regulates erythropoiesis by controlling translation of the erythroid transcription factor GATA1. Rnh1-deficient mice die between embryonic days E8.5 and E10 due to impaired production of mature erythroid cells from progenitor cells. In Rnh1-deficient embryos, mRNA levels of Gata1 are normal, but GATA1 protein levels are decreased. At the molecular level, we found that RNH1 binds to the 40S subunit of ribosomes and facilitates polysome formation on Gata1 mRNA to confer transcript-specific translation. Further, RNH1 knockdown in human CD34+ progenitor cells decreased erythroid differentiation without affecting myelopoiesis. Our results reveal an unsuspected role for RNH1 in the control of GATA1 mRNA translation and erythropoiesis.

Authors

Vijaykumar Chennupati, Diogo F.T. Veiga, Kendle M. Maslowski, Nicola Andina, Aubry Tardivel, Eric Chi-Wang Yu, Martina Stilinovic, Cedric Simillion, Michel A. Duchosal, Manfredo Quadroni, Irene Roberts, Vijay G. Sankaran, H. Robson MacDonald, Nicolas Fasel, Anne Angelillo-Scherrer, Pascal Schneider, Trang Hoang, Ramanjaneyulu Allam

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Figure 3

Rnh1 is expressed in embryonic erythropoiesis and regulates erythroid differentiation.

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Rnh1 is expressed in embryonic erythropoiesis and regulates erythroid d...
(A and B) qRT-PCR analysis for Rnh1 on whole embryos from different embryonic days as shown (A) and E9.5 yolk sacs and embryos proper (B). mRNA levels are normalized to 18S rRNA expression (n = 3–4). Data are shown as mean ± SEM. (C) Immunostaining of a WT E10.5 yolk sac with RNH1 and the erythroid marker TER119. Original magnification ×20. (D) Flow cytometry analysis for HSPCs on E9.5 yolk sac cells (n = 3–4). (E) Flow cytometry analysis for CD31-negative erythroid cells on E8.5 and E9.5 yolk sac cells (n = 3–4). Data are shown as mean ± SEM. (F) Cytospins from yolk sac cells were stained with Pappenheim stain (left). Binucleated erythroblasts are indicated by asterisks. Representative bar graph showing percentage of binucleated cells (right) (n = 3). Original magnification ×400. Data are shown as mean ± SEM. P values were determined by 2-tailed t test.