Nonsense-mediated and nonstop decay of ribosomal protein S19 mRNA in Diamond-Blackfan anemia.
Mutations in the ribosomal protein (RP)S19 gene have been found in about 25% of the cases of Diamond-Blackfan anemia (DBA), a rare congenital hypoplastic anemia that includes variable physical malformations. Various mutations have been identified in the RPS19 gene, but no investigations regarding the effect of these alterations on RPS19 mRNA levels have been performed. It is well established that mutated mRNA containing a premature stop codon (PTC) or lacking a stop codon can be rapidly degraded by specific mechanisms called nonsense mediated decay (NMD) and nonstop decay. To study the involvement of such mechanisms in DBA, we analyzed immortalized lymphoblastoid cells and primary fibroblasts from patients presenting different kinds of mutations in the RPS19 gene, generating allelic deletion, missense, nonsense, and nonstop messengers. We found that RPS19 mRNA levels are decreased in the cells with allelic deletion and, to a variable extent, also in all the cell lines with PTC or nonstop mutations. Further analysis showed that translation inhibition causes a stabilization of the mutated RPS19 mRNA. Our findings indicate that NMD and nonstop decay affect the expression of mutated RPS19 genes; this may help to clarify genotype-phenotype correlations in DBA.
Chatr-Aryamontri
Andrew
A
Department of Biology, University Tor Vergata, Roma, Italy.
Angelini
Mara
M
Garelli
Emanuela
E
Tchernia
Gil
G
Ramenghi
Ugo
U
Dianzani
Irma
I
Loreni
Fabrizio
F
D000483:Alleles; D029503:Anemia, Diamond-Blackfan / Q000235:genetics*; D015152:Blotting, Northern; D002460:Cell Line; D002478:Cells, Cultured; D018388:Codon, Terminator / Q000235:genetics; D004252:DNA Mutational Analysis; D018076:DNA, Complementary; D017353:Gene Deletion; D006801:Humans; D009154:Mutation; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012269:Ribosomal Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA
D018388:Codon, Terminator; D018076:DNA, Complementary; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C040343:ribosomal protein S19