MOLECULAR-CLONING AND NUCLEOTIDE-SEQUENCE OF CHICKEN AVIDIN-RELATED GENES 1-5

Using avidin cDNA as a hybridisation probe, we detected a gene family whose putative products are related to the chicken egg-white avidin. T wo overlapping genomic clones were found to contain five genes (avidin -related genes 1-5, avr1-avr5), which have been cloned, characterized and sequenced. All of the genes have a four-exon structure with an ove rall identity with the avidin cDNA of 88-92%. The genes appear to have no pseudogenic features and, in fact, two of these genes have been sh own to be transcribed. The putative proteins share a sequence identity of 68-78% with avidin. The amino acid residues responsible for the bi otin-binding activity of avidin and the bacterial biotin-binding prote in, streptavidin, are highly conserved. Since avidin is induced in bot h a progesterone-specific manner and in connection with inflammation, these genes offer a valuable tool to study complex gene regulation in vivo.