Analysis of inhibitor of apoptosis protein family expression during mammary gland development.
BACKGROUND
Inhibitors-of-Apoptosis-Proteins (IAPs) are an evolutionarily conserved family of proteins capable of regulating several facets of apoptosis. IAPs are frequently dysregulated in cancer, but their role in the regulation of apoptosis during developmental processes is not fully understood. Here we examined the expression of IAPs during the post-natal development of the mouse mammary gland, which is a tissue that exhibits a profound induction of apoptosis during involution.


RESULTS
Six out of eight mammalian IAP family members are expressed in the mammary gland. Notably, quantitative PCR and immunoblotting revealed that XIAP, c-IAP1 and c-IAP2 are down-regulated in pregnancy and lactation, and prior to the onset of involution. In cultured mammary epithelial cells (MECs), XIAP levels decreased in response to inhibition of growth factor signalling. Maintaining XIAP levels in MECs by expressing exogenous XIAP protected them from all apoptotic stimuli tested.


CONCLUSIONS
These data suggest that the developmental regulation of IAP expression in vivo contributes to naturally occurring programmes of cell death.
Owens
Thomas W
TW
Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK.
Foster
Fiona M
FM
Tanianis-Hughes
Jolanta
J
Cheung
Julia Y
JY
Brackenbury
Lisa
L
Streuli
Charles H
CH
D000818:Animals; D015536:Down-Regulation; D005260:Female; D018507:Gene Expression Regulation, Developmental; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics* / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000254:growth & development* / Q000378:metabolism; D051379:Mice; D011247:Pregnancy
D051034:Inhibitor of Apoptosis Proteins