The imprinted Air ncRNA is an atypical RNAPII transcript that evades splicing and escapes nuclear export.
Expression of the Air ncRNA is necessary to silence multiple genes in cis in the imprinted Igf2r cluster. However, its mode of action is unknown. Here, we characterize co- and post-transcriptional features of Air that identify it as a new member of the class of nuclear regulatory RNAs. We show that Air is transcribed from a DNA methylation-sensitive promoter by RNA polymerase II (RNAPII). However, although it is capped and polyadenylated similar to other RNAPII transcripts, the majority of Air transcripts evade cotranscriptional splicing resulting in a mature 108 kb ncRNA. As a consequence, the mature unspliced Air is nuclear localized and highly unstable. These features show that Air is an atypical RNAPII transcript whose properties indicate that its mode of action in gene silencing may not depend on the RNA per se but instead is related to its actual transcription.
Seidl
Christine I M
CI
CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, c/o Institute of Genetics, Max F Perutz Laboratories, Vienna Biocenter, Dr Bohr-Gasse 9/4, A-1030 Vienna, Austria.
Stricker
Stefan H
SH
Barlow
Denise P
DP
D021581:Active Transport, Cell Nucleus; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D019175:DNA Methylation; D020868:Gene Silencing; D018392:Genomic Imprinting; D051379:Mice; D008954:Models, Biological; D041681:NIH 3T3 Cells; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing; D020871:RNA Stability; D022661:RNA, Untranslated / Q000235:genetics* / Q000378:metabolism*
D012322:RNA Precursors; D022661:RNA, Untranslated; D012319:RNA Polymerase II