Potassium channel mRNAs with AU-rich elements and brain-specific expression.
GIRK2 (G protein-gated inwardly rectifying K(+) channel 2) located on the Down syndrome region 21q22.2 in humans has been reported to have several alternative transcripts and transcripts longer than 4 kb that do not have the poly-A tail. We sequenced GIRK2 transcripts with a long 3'-untranslated region (3'-UTR) containing multiple adenylate uridylate-rich elements (AREs) with the poly-A tail. In a 16-kb transcript, 28 AUUUA pentanucleotides, 9 AUUUUA hexanucleotides, 5 AUUUUUA heptanucleotides, and 3 UUAUUUA[U/A][U/A] nonanucleotides were found. Northern blot and in situ hybridization revealed abundant expression of the 16-kb transcripts in the rat brain despite no detectable signals in other tissues examined. The AREs have been reported to mediate the turnover of mRNAs encoding proteins regulating cellular proliferation/differentiation and body response to inflammatory and environmental stimuli. This is the first study indicating that ion channel transcripts have multiple AREs.
Suda
Shiro
S
Department of Psychiatry, Jichi Medical School, Yakushiji 3311-1, Minamikawachi, Tochigi 239-0498, Japan.
Nibuya
Masashi
M
Suda
Haruhiko
H
Takamatsu
Ken
K
Miyazaki
Toru
T
Nomura
Soichiro
S
Kawai
Nobufumi
N
D020413:3' Untranslated Regions / Q000032:analysis; D000818:Animals; D001921:Brain / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011061:Poly A / Q000235:genetics; D015221:Potassium Channels / Q000235:genetics* / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D014018:Tissue Distribution
D020413:3' Untranslated Regions; D018076:DNA, Complementary; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger; D011061:Poly A