Ribosomal protein S19 and S24 insufficiency cause distinct cell cycle defects in Diamond-Blackfan anemia

Jitendra Badhai , Anne-Sophie Fröjmark , Edward Davey , Jens Schuster , Niklas Dahl

Diamond-Blackfan anemia (DBA) is a severe congenital anemia characterized by a specific decrease of erythroid precursors. The disease is also associated with growth retardation, congenital malformations, a predisposition for malignant disease and heterozygous mutations in either of the ribosomal protein (RP) genes , , , , and We show herein that primary fibroblast from DBA patients with truncating mutations in or in have a marked reduction in proliferative capacity. Mutant fibroblasts are associated with extended cell cycles and normal levels of p53 when compared to w.t. cells. mutant fibroblasts accumulate in the G1 phase, whereas the mutant cells show an altered progression in the S phase resulting in reduced levels in the G2/M phase. RPS19 deficient cells exhibit reduced levels of Cyclin-E, CDK2 and retinoblastoma (Rb) protein supporting a cell cycle arrest in the G1 phase. In contrast, RPS24 deficient cells show increased levels of the cell cycle inhibitor p21 and a seemingly opposing increase in Cyclin-E, CDK4 and CDK6. In combination, our results show that RPS19 and RPS24 insufficient fibroblasts have an impaired growth caused by distinct blockages in the cell cycle. We suggest this proliferative constraint to be an important contributing mechanism for the complex extra-hematological features observed in DBA.

Mots clés: RPS19; RPS24; Diamond-Blackfan Anemia; Proliferation; Cell cycle; Cell cycle regulation

Jitendra Badhai, Anne-Sophie Fröjmark, Edward Davey, Jens Schuster, Niklas Dahl. Ribosomal protein S19 and S24 insufficiency cause distinct cell cycle defects in Diamond-Blackfan anemia. Biochimica et Biophysica Acta - Molecular Basis of Disease, 2009, 1792 (10), pp.1036. ⟨10.1016/j.bbadis.2009.08.002⟩. ⟨hal-00521092⟩