Identification and characterization of a putative C. elegans potassium channel gene (Ce-slo-2) distantly related to Ca(2+)-activated K(+) channels.
Two putative homologues of large conductance Ca(2+)-activated K(+) channel alpha-subunit gene (slowpoke or slo) were revealed by C. elegans genome sequencing. One of the two genes, F08B12.3 (Ce-slo-2), shows a relatively low amino acid sequence similarity to other Slo sequences and lacks key functional motifs, which are important for calcium and voltage sensing. However, its overall structure and regions of homology, which are conserved in all Slo proteins, suggest that Ce-SLO-2 should belong to the Slo channel family. We have cloned a full-length cDNA of the Ce-slo-2, which encodes a protein containing six putative transmembrane segments with a K(+)-selective pore and a large C-terminal cytosolic domain. Green fluorescent protein (GFP) and whole-mount immunostaining analyses revealed that Ce-slo-2 is specifically expressed in neuronal cells at the nerve ring, at the ventral nerve cord of the mid-body, and at the tail region. We have also identified a putative human counterpart of Ce-slo-2 from a human brain EST database, which shows a stretch of highly conserved amino acid residues. Northern blot and mRNA dot blot analyses revealed a strong and specific expression in brain and skeletal muscle. Taken together, our data suggest that Ce-slo-2 may constitute an evolutionarily conserved gene encoding a potassium channel that has specific functions in neuronal cells.
Lim
H H
HH
Department of Life Science, Kwangju Institute of Science and Technology (K-JIST), Kwangju, South Korea.
Park
B J
BJ
Choi
H S
HS
Park
C S
CS
Eom
S H
SH
Ahnn
J
J
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005260:Female; D015870:Gene Expression; D017238:Genes, Helminth / Q000235:genetics*; D049452:Green Fluorescent Proteins; D006801:Humans; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000235:genetics*; D024681:Potassium Channels, Calcium-Activated; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008164:Luminescent Proteins; D026901:Membrane Transport Proteins; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D011993:Recombinant Fusion Proteins; C402625:SLO-2 protein, C elegans; C494845:slo-1 protein, C elegans; D049452:Green Fluorescent Proteins