Distinct spatial and temporal expression patterns of K+ channel mRNAs from different subfamilies.
Different types of K+ channels play important roles in many aspects of excitability. The isolation of cDNA clones from Drosophila, Aplysia, Xenopus, and mammals points to a large multigene family with several distinct members encoding K+ channels with unique electrophysiological and pharmacological properties. Given the pivotal role K+ channels play in the fine tuning of electrical properties of excitable tissues, we studied the spatial and temporal basis of K+ channel diversity. We report the isolation of two putative K+ channels that define two new subfamilies based upon amino acid sequence similarities with other known K+ channels. Northern blot and in situ hybridization studies revealed differences in the spatial and temporal expression patterns for these two new clones along with mRNAs from other K+ channel subfamilies. Two of the K+ channels studied are predominantly expressed in the brain. One of the "brain-specific" K+ channels is first expressed after about 2 weeks of postnatal cerebellar development and remains at levels about 10-fold higher in the cerebellum than in the rest of the brain.
Drewe
J A
JA
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030.
Verma
S
S
Frech
G
G
Joho
R H
RH
D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia / Q000235:genetics; D015152:Blotting, Northern; D001921:Brain / Q000502:physiology*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004330:Drosophila / Q000235:genetics; D015723:Gene Library; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D015221:Potassium Channels / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D051669:Shab Potassium Channels; D014158:Transcription, Genetic; D014981:Xenopus
C496991:Kcnb1 protein, rat; D015221:Potassium Channels; D012333:RNA, Messenger; D051669:Shab Potassium Channels; D004247:DNA