Cloning and expression of cDNA and genomic clones encoding three delayed rectifier potassium channels in rat brain.
Rat brain cDNA and genomic clones encoding three K+ channels, Kv1, Kv2, and Kv3, have been isolated by screening with Shaker probes and encode proteins of 602, 530, and 525 amino acids. Each of the deduced protein sequences contains six hydrophobic domains (including an S4-type region characteristic of many voltage-gated channels) and are 68%-72% identical to each other overall. Transcripts of approximately 3.5, approximately 6.5, and approximately 9.5 kb encode Kv1, Kv2, and Kv3, respectively. The Kv2 mRNA is expressed only in brain, whereas the Kv1 and Kv3 transcripts are found in several other tissues as well. There is a marked increase in the amount of Kv1 mRNA in cardiac tissue during development and a similar, but less pronounced, increase of both this mRNA and the Kv2 transcript in brain. RNAs synthesized in vitro from the three clones induce voltage- and time-dependent, delayed rectifier-like K+ currents when injected into Xenopus oocytes, demonstrating that they encode functional K+ channels.
Swanson
R
R
Department of Pharmacology, Merck Sharp and Dohme Research Laboratories, West Point, Pennsylvania 19486.
Marshall
J
J
Smith
J S
JS
Williams
J B
JB
Boyle
M B
MB
Folander
K
K
Luneau
C J
CJ
Antanavage
J
J
Oliva
C
C
Buhrow
S A
SA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000502:physiology*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D009865:Oocytes / Q000502:physiology; D009928:Organ Specificity; D015221:Potassium Channels / Q000502:physiology*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014981:Xenopus
D008565:Membrane Proteins; D015345:Oligonucleotide Probes; D015221:Potassium Channels; D012333:RNA, Messenger; D004247:DNA