title: Altered expression of two zinc transporters, SLC30A5 and SLC30A6, underlies a mammary gland disorder of reduced zinc secretion into milk.
abstract: Two cases of zinc deficiency in breastfed neonates were investigated where zinc levels in the mothers' milk were reduced by more than 75 % compared to normal. The objective of this study was to find the molecular basis of the maternal zinc deficiency condition. Significant reductions in mRNA expression and protein levels of the zinc transporters SLC30A5 and SLC30A6 were found in maternal tissue, suggesting a causal link to the zinc-deficient milk. Novel splice variants of the SLC30A6 transcript were detected. No modifications were found in coding regions, or in transcription binding sites of promoter regions or in 5' and 3' untranslated regions of both transporters in lymphoblasts and fibroblasts isolated from both mothers. Altered DNA methylation in SLC30A5 at two CpG sites was detected and may account for the reduced levels of SLC30A5 mRNA and protein in lymphoblasts. Reduced SLC30A6 mRNA and protein levels in lymphoblasts may be secondary to reduced SLC30A5 expression, as they function as a heterodimer in zinc transport. In conclusion, two cases of zinc deficiency are linked to low levels of the SLC30A5 and SLC30A6 zinc transporters. These two zinc transporters have not been previously associated with zinc deficiency in milk.
authors: Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia.
authors: Loveleen
authors: L
authors: Kumar
authors: Agnes
authors: A
authors: Michalczyk
authors: Jill
authors: J
authors: McKay
authors: Dianne
authors: D
authors: Ford
authors: Taiho
authors: T
authors: Kambe
authors: Lee
authors: L
authors: Hudek
authors: George
authors: G
authors: Varigios
authors: Philip E
authors: PE
authors: Taylor
authors: M Leigh
authors: ML
authors: Ackland