Induction of Mouse Ca2+-Sensitive Chloride Channel 2 Gene during Involution of Mammary Gland

To understand molecular mechanisms that regulate mammary gland involution, we identified involution-induced cDNA clones by suppression subtractive hybridization methods. Nucleotide sequencing of a clone revealed that it was 97% identical to Ca2+-sensitive chloride channel 1 (mCLCA1) gene that has been identified in lung tissue. We concluded that our clone was derived from different gene with mCLCA1 and named it mCLCA2. We confirmed that expression of mCLCA2 gene was predominant in mammary gland while mCLCA1 mRNA was mainly detected in lung tissues by RT-PCR. Northern analysis showed that the mCLCA2 gene was induced at involution phase compared to pregnant and lactating phases of mammary gland. Under serum starvation, HC11 mammary epithelial cells showed DNA fragmentation and induction of mCLCA2 expression.