cDNA sequence identity of a vitamin D-dependent calcium-binding protein in the chick to calbindin D-9K.

1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] is a steroid hormone that modulates the expression of specific proteins by a genomic mechanism of action. Calbindin D-9K is a calcium-binding protein that heretofore has only been found in mammalian tissues and whose gene expression is regulated by 1,25(OH)2D3 in a tissue specific fashion. By combined reverse transcription and polymerase chain reaction, calbindin D-9K gene expression was demonstrated for the first time to be present in several chicken tissues. Subcloning and sequencing of a partial 160 bp-cDNA PCR product revealed that the cDNA corresponds to calbindin D-9K-cDNA. This constitutes the first evidence of calbindin D-9K gene presence and expression in the avian class.