Sequence comparison of avian interferon regulatory factors and identification of the avian CEC-32 cell as a quail cell line

Interferon (IFN) regulatory factor-1 (IRF-1) is a well-characterized member of the IRF family. Previously, we ha have cloned cDN4 of several members o f the chicken IRF (ChIRF) family and studied the function of ChIRF-1 in the avian cell line CEC-32, The IRF-1 proteins from primary chicken embryo fib roblasts (CEF) and CEC-32 cells differed in their electrophoretic mobility. To characterize the different forms of IRF-1 in avian cells, we compared t he sequences of IRF-1 cDNA from CEC-32 cells, primary CEF, and quail fibrob lasts (QEF), The deduced amino acid sequences of IRF-1 cDNA from chicken an d quail show high similarity. Comparison of genomic sequences of IRF-1 and IFN consensus sequence binding protein (ICSBP) also confirm the relatedness of the members of the IRF family in quail and chicken. Based on these data , it is concluded that the avian fibroblast cell line CEC-32 is derived fro m quail. This conclusion is further supported by deoxynucleotide sequence c omparison of a DNA fragment in an avian MHC class II gene and by fluorescen ce in situ hybridization (FISH) using the vertebrate telomeric (TTAGGG) rep eat. Chromosome morphology and the lack of interstitial hybridization signa ls in macrochromosomes suggest that the CEC-32 cell line has probably been derived from Japanese quail.