Intron-exon structure of the porcine I kappa B alpha-encoding gene

Genomic clones of ECI-6 (endothelial cell inducible), the porcine I kappa B alpha gene that encodes a cytoplasmic inhibitor of the transcription factor NF-kappa B, were isolated, spanning the entire transcribed region plus 2.1 and 0.35 kb of 5'- and 3'-flanking sequences, respectively. The gene contains five introns ranging in size from 0.6 to 0.1 kb. Four of the introns are located in the coding regions for four of the five ankyrin-like repeats in the central part of the I kappa B alpha protein at similar positions. The fifth intron is located in the C-terminal region. Southern blot analysis indicates the presence of a single copy of ECI-6/I kappa B alpha in the porcine genome.