title: Robo3A and Robo3B expression is regulated via alternative promoters and mRNA stability.
abstract: BACKGROUND
  The transmembrane receptor family Roundabout (Robo) was described to have an essential role in the developing nervous system. Recent studies demonstrated that Robo3 shows an altered expression in rheumatoid arthritis as well as in melanoma.
  Until today no detailed studies of the two Robo3 isoforms (Robo3A and Robo3B) and their roles in rheumatoid arthritis synovial fibroblasts, respectively malignant melanoma are available. To get a better understanding regarding the role of Robo3A and Robo3B in the molecular process of rheumatoid arthritis and melanoma the exact characterization of expression and regulation is object of this study.
  
  
  RESULTS
  mRNA and protein expression of the transcriptional variants were analyzed by quantitative RT-PCR respectively western blotting and revealed particularly enhanced expression of Robo3B in rheumatoid arthritis and melanoma. Promoter assays and inhibitor studies also disclosed that there is apparently a cell- and isoform-specific regulation of the Robo3 expression. Finally, dissimilar mRNA stabilities of Robo3A and Robo3B are identified as decisive posttranscriptional gene expression control.
  
  
  CONCLUSIONS
  In summary, this study supported an isotype specific role of Robo3B in disease hinting to different functional roles of each isoform.
authors.affiliation: Institute of Biochemistry, Emil-Fischer-Zentrum, Friedrich-Alexander University of Erlangen-Nürnberg, Fahrstrasse 17, 91054 Erlangen, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Ruedel
authors.affiliation: Institute of Biochemistry, Emil-Fischer-Zentrum, Friedrich-Alexander University of Erlangen-Nürnberg, Fahrstrasse 17, 91054 Erlangen, Germany.
authors.forename: Mandy
authors.initials: M
authors.lastname: Schott
authors.affiliation: Institute of Pathology, Friedrich-Alexander University of Erlangen-Nürnberg, Universitätsstrasse, 91054 Erlangen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schubert
authors.affiliation: Institute of Biochemistry, Emil-Fischer-Zentrum, Friedrich-Alexander University of Erlangen-Nürnberg, Fahrstrasse 17, 91054 Erlangen, Germany.
authors.forename: Anja Katrin
authors.initials: AK
authors.lastname: Bosserhoff
keywords: Malignant melanoma; Repellent factor; Rheumatoid arthritis; Robo