Genomic structure of a potassium channel toxin from Heteractis magnifica

FEBS Lett. 1997 Nov 24;418(1-2):183-8. doi: 10.1016/s0014-5793(97)01365-3.


We provide information on the gene encoding the K+ channel toxin, HmK, of the sea anemone Heteractis magnifica. A series of DNA amplifications by PCR, which included the amplification of the 5'-untranslated region of the gene, showed that an intron of 402 nucleotides separated the sequence that encodes the matured toxin from the signal peptide sequence. A second 264 nucleotide intron interrupted the 5'-untranslated region of the previously reported HmK cDNA. Two possible transcription-initiation sites were identified by primer extension analysis. Corresponding TATA-box consensus sequences, characteristic of a promoter region, were also located from PCR products of uncloned libraries of adaptor-ligated genomic DNA fragments. The coding region for matured HmK is intronless. The same is also true for other sea anemone toxins reported thus far. More notably, a similar intron-exon organization is present in other ion channel-blocking toxins from scorpions implying that molecules having similar functions share a similar organization at the genomic level suggesting a common path of evolution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cnidarian Venoms / biosynthesis
  • Cnidarian Venoms / chemistry
  • Cnidarian Venoms / genetics*
  • Consensus Sequence
  • DNA, Complementary
  • Exons
  • Genome*
  • Introns
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Potassium Channel Blockers
  • Sea Anemones / genetics*
  • TATA Box
  • Transcription, Genetic


  • Cnidarian Venoms
  • DNA, Complementary
  • HmK toxin, sea anemone
  • Potassium Channel Blockers

Associated data

  • GENBANK/AF020047