Functional and developmental study of tetratricopeptide repeat domain 9A in mouse model.

Abstract

Tetratricopeptide repeat domain 9A (TTC9A) is a hormone regulated gene in breast cancer cells. The gene is significantly over-expressed in the breast cancer tissues compared to the adjacent normal tissues. In mice, TTC9A is differentially regulated in the mammary gland development indicating its sensitivity to the hormone status. Administration of estrogen significantly up-regulated TTC9A expression in mice mammary gland and uterus. To understand the function of TTC9A, a knockout mouse was generated. TTC9A deficient mammary gland showed significant increase in mammary ductal elongation and branching on estrogen and progesterone treatment, demonstrating aberration in hormone receptor signaling in absence of TTC9A.These observations suggest that TTC9A negatively regulates mammary gland development and the possibility that TTC9A may exert negative effects on mammary neoplasia which may require further investigation.