Combined Rps14/Csnk1a1/miR-145/146a deficiency recapitulated the cardinal features of the 5q- syndrome, including (1) more severe anemia with faster kinetics than Rps14 haploinsufficiency alone and (2) pathognomonic megakaryocyte morphology.
Haploinsufficiency of the ribosomal protein gene RPS14 plays a critical role in the development of anemia in the 5q- syndrome, and haploinsufficiency of CUX1 is important in some patients with MDS and AML with complete or partial loss of chromosome 7.
A mouse model of the human 5q- syndrome has been generated by large-scale deletion of the Cd74-Nid67 interval (containing Rps14) and the crossing of these '5q- mice' with p53-deficient mice ameliorated the erythroid progenitor defect.
Heterozygous loss of the RPS14 gene on 5q leads to activation of p53 in the erythroid lineage and the macrocytic anemia characteristic of the 5q-syndrome.
Recurrent deletions of 5q in myeloid malignancies encompass two separate regions: deletion of 5q33, which is associated with the 5q− syndrome and haploinsufficiency of RPS14, and deletion of a more proximal locus at 5q31.
We found that p53 accumulates selectively in the erythroid lineage in primary human hematopoietic progenitor cells after expression of shRNAs targeting RPS14, the ribosomal protein gene deleted in the 5q-syndrome, or RPS19, the most commonly mutated gene in DBA.
A mouse model of the human 5q- syndrome has now been created by chromosomal engineering involving a large-scale deletion of the Cd74-Nid67 interval (containing RPS14).
Haploinsufficiency of the ribosomal protein S14RPS14 gene, located in the common deleted region of chromosome 5q, is a potential causal factor of 5q- syndrome.
In 5q- syndrome haploinsufficiency of the ribosomal gene RPS14 appears to cooperate with loss of two micro-RNAs miR-145 and miR-146 to induce key features of the disease.
A systematic RNA interference screen to interrogate the function of each gene in the common deleted region (CDR) for the 5q- syndrome identified RPS14 as a critical haploinsufficiency disease gene for the erythroid failure, which is a characteristic of this syndrome.
This review examines the potential role of several genes, including RPS14, in the pathogenesis of the 5q- syndrome and recent advances in clinical management, with particular emphasis on the role and mechanism of action of lenalidomide.
In addition, we identified a block in the processing of pre-ribosomal RNA in RPS14-deficient cells that is functionally equivalent to the defect in Diamond-Blackfan anaemia, linking the molecular pathophysiology of the 5q- syndrome to a congenital syndrome causing bone marrow failure.
Candidate genes showing haploinsufficiency in the 5q- syndrome included the tumour suppressor gene SPARC and RPS14, a component of the 40S ribosomal subunit.
Our findings indicate that Len restores MDM2 functionality in the 5q- syndrome to overcome p53 activation in response to nucleolar stress, and therefore may warrant investigation in other disorders of ribosomal biogenesis.