總結(jié) |
This locus has a highly complex imprinted expressionpattern. It gives rise to maternally, paternally, and biallelicallyexpressed transcripts that are derived from four alternativepromoters and 5' exons. Some transcripts contains a differentiallymethylated region (DMR) at their 5' exons, and this DMR is commonlyfound in imprinted genes and correlates with transcript expression.An antisense transcript is produced from an overlapping locus onthe opposite strand. One of the transcripts produced from thislocus, and the antisense transcript, are paternally expressednoncoding RNAs, and may regulate imprinting in this region. Inaddition, one of the transcripts contains a second overlapping ORF,which encodes a structurally unrelated protein - Alex. Alternativesplicing of downstream exons is also observed, which results indifferent forms of the stimulatory G-protein alpha subunit, a keyelement of the classical signal transduction pathway linkingreceptor-ligand interactions with the activation of adenylylcyclase and a variety of cellular reponses. Multiple transcriptvariants encoding different isoforms have been found for this gene.Mutations in this gene result in pseudohypoparathyroidism type 1a,pseudohypoparathyroidism type 1b, Albright hereditaryosteodystrophy, pseudopseudohypoparathyroidism, McCune-Albrightsyndrome, progressive osseus heteroplasia, polyostotic fibrousdysplasia of bone, and some pituitary tumors.
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