Aquarius Homolog (AQR)

IBP160 migrated as a 160-kD protein by SDS-PAGE. Indirect immunofluorescence localized IBP160 to speckle-like regions of the nucleoplasm.The deduced protein shares weak homology with viral RNA-dependent RNA polymerases, including conservation of polymerase active-site motifs. Aqr also has 2 putative nuclear localization signals. Expression of Aqr was detected in mouse embryos at 8.5 days postcoitum, when neural crest cells were visible at the lateral ridges of the neural plate. Aqr was expressed in mesoderm, in the neural crest and its target tissues, and in neuroepithelium.The transcript contains repetitive elements in its 3-prime UTR, and the deduced 1,421-amino acid protein shares significant similarity with mouse aquarius. RT-PCR detected highest AQR expression in kidney.