title: 5'UTR variants of ribosomal protein S19 transcript determine translational efficiency: implications for Diamond-Blackfan anemia and tissue variability.
abstract: BACKGROUND
  Diamond-Blackfan anemia (DBA) is a lineage specific and congenital erythroblastopenia. The disease is associated with mutations in genes encoding ribosomal proteins resulting in perturbed ribosomal subunit biosynthesis. The RPS19 gene is mutated in approximately 25% of DBA patients and a variety of coding mutations have been described, all presumably leading to haploinsufficiency. A subset of patients carries rare polymorphic sequence variants within the 5'untranslated region (5'UTR) of RPS19. The functional significance of these variants remains unclear.
  
  
  RESULTS
  We analyzed the distribution of transcriptional start sites (TSS) for RPS19 mRNAs in testis and K562 cells. Twenty-nine novel RPS19 transcripts were identified with different 5'UTR length. Quantification of expressed w.t. 5'UTR variants revealed that a short 5'UTR correlates with high levels of RPS19. The total levels of RPS19 transcripts showed a broad variation between tissues. We also expressed three polymorphic RPS19 5'UTR variants identified in DBA patients. The sequence variants include two insertions (c.-147_-146insGCCA and c.-147_-146insAGCC) and one deletion (c.-144_-141delTTTC). The three 5'UTR polymorphisms are associated with a 20-30% reduction in RPS19 protein levels when compared to the wild-type (w.t.) 5'UTR of corresponding length.
  
  
  CONCLUSIONS
  The RPS19 gene uses a broad range of TSS and a short 5'UTR is associated with increased levels of RPS19. Comparisons between tissues showed a broad variation in the total amount of RPS19 mRNA and in the distribution of TSS used. Furthermore, our results indicate that rare polymorphic 5'UTR variants reduce RPS19 protein levels with implications for Diamond-Blackfan anemia.
authors.affiliation: Department of Immunology, Genetics and Pathology, Science for Life Laboratory and Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Jitendra
authors.initials: J
authors.lastname: Badhai
authors.forename: Jens
authors.initials: J
authors.lastname: Schuster
authors.forename: Olof
authors.initials: O
authors.lastname: Gidlöf
authors.forename: Niklas
authors.initials: N
authors.lastname: Dahl
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics*; D029503:Anemia, Diamond-Blackfan / Q000235:genetics*; D001483:Base Sequence; D002460:Cell Line; D020869:Gene Expression Profiling; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity / Q000235:genetics*; D014176:Protein Biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D024363:Transcription Initiation Site
chemical_list: D020121:5' Untranslated Regions; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C040343:ribosomal protein S19