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RXRβ isoforms in neuroblastoma cells and evidence for a novel 3′‐end transcript
Author(s) -
Rana Birju,
Pearson Andrew D.J.,
Redfern Christopher P.F.
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02882-4
Subject(s) - retinoid x receptor , gene isoform , biology , neuroblastoma , microbiology and biotechnology , intron , transcription factor , cell culture , gene , genetics , nuclear receptor
RXRβ is predominantly involved in retinoid responses in neuroblastoma cells, in particular the N‐type SH SY 5Y cells and the S‐type SH S EP cells, both derivatives of a mixed phenotype neuroblastoma cell line. The aim of this study was to identify RXRβ isoforms expressed in neuroblastoma cells and to characterise a putative novel RXRβ transcript. RXRβ1 and RXRβ2 were expressed in these neuroblastoma cells. An isoform with an insertion into the ligand binding domain, RXRβ SLSR (referred to in previous studies as RXRβ3), was expressed at a similar level to RXRβ. A novel RXRβ transcript was identified by RNase protection assays and was at least as abundant as the expected RXRβ transcript and expressed in other cell types. Evidence suggests that this novel transcript was transcribed from an internal promoter between exons 5 and 6, contained a retained intron (intron 6) and was alternatively spliced with and without the SLSR insertion. These data show that the pattern of RXRβ expression is complex. The relative abundance of the novel RXRβ transcript suggests that it may be an important aspect of RXRβ function or regulation in a range of cell types.