Alternative non-coding splice variants of Nespas, an imprinted gene antisense to Nesp in the Gnas imprinting cluster.
The Gnas locus on mouse Chr 2 represents a unique cluster of overlapping imprinted genes. Three of these in the order Nesp--Gnasxl--Gnas are transcribed in the sense direction with Nesp having maternal-specific expression, Gnasxl having paternal expression, and Gnas as being biallelically expressed in most tissues. A fourth imprinted gene, Nespas, is paternally expressed, lies antisense to Nesp, and expresses an unspliced transcript. Large unspliced antisense transcripts are emerging as a feature of imprinted gene clusters, and such non-coding RNAs may have a cis-regulatory function. Here we show that, in addition to an unspliced form of Nepas, we can detect five alternatively spliced forms of Nespas up to 1.4 kb in length that are non-coding. The splice variants are paternally expressed; they start approximately 2 kb upstream of Gnasxl in a region of maternal methylation and end 2.5 kb beyond the ATG of Nesp. These variants do not correspond to exons of the human antisense transcript although they start in the same region; the Nespas transcript, like its human counterpart, is spliced in various alternative patterns. The identification of a set of small spliced imprinted transcripts in the human and now in the mouse suggests that these antisense transcripts are functionally important.
Williamson
Christine M
CM
MRC Mammalian Genetics Unit, Harwell, Didcot, Oxfordshire, OX11 0RD, UK.
Skinner
Judith A
JA
Kelsey
Gavin
G
Peters
Josephine
J
D017398:Alternative Splicing / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002864:Chromogranins; D019175:DNA Methylation; D016373:DNA, Antisense / Q000235:genetics*; D005260:Female; D019205:GTP-Binding Protein alpha Subunits, Gs; D018392:Genomic Imprinting; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics*; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D009419:Nerve Tissue Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA
D002864:Chromogranins; D016373:DNA, Antisense; D009419:Nerve Tissue Proteins; C498642:Gnas protein, mouse; D019205:GTP-Binding Protein alpha Subunits, Gs; D020962:Heterotrimeric GTP-Binding Proteins