GENOMIC ORGANIZATION OF THE KTX(2) GENE, ENCODING A SHORT SCORPION TOXIN ACTIVE ON K+ CHANNELS

A single intron of 87 bp, close to the region encoding the C-terminal part of the signal peptide, was found in the gene of the 'short' scorp ion toxin kaliotoxin 2 of Androctonus australis acting on various type s of K+ channels, Its A+T content was particularly high (up to 86%), B y walking and ligation-mediated PCR, the promoter sequences of the kal iotoxin 2 gene of Androctonus australis were studied, The transcriptio n unit of the gene is 390 bp long, Consensus sequences were identified , The genes of 'short' scorpion toxins active on K+ channels are organ ized similarly to those of the 'long' scorpion toxins active on Na+ ch annels and not like those of structurally related insect defensins, wh ich are intronless.