title: Nature of Cx30-containing channels in the adult mouse mammary gland.
abstract: Oligonucleotide microarray analysis uniquely shows that several members of the connexin family of gap junction proteins are expressed by the epithelium during mouse mammary gland development. Connexin 26 (Cx26) is present throughout pregnancy and lactation, is then undetectable shortly after weaning, but reappears during involution. Additionally, Cx30 is abundant in late-pregnant and early lactating gland epithelium. From mid-pregnancy into early lactation, Cx26 and Cx30 co-localize in junctional plaques between epithelial cells, forming hemichannels of mixed connexin content. Microarray analysis also shows Cx32 is developmentally restricted to parturition, suggesting that specific modification of gap junction channel composition and/or intercellular communication pathways occurs at parturition. Specifically, heteromeric channels of all pairwise combinations are formed when these connexins are expressed within the same cells. Of these hemichannels, Cx26/Cx32 pores are increasingly sensitive to closure by taurine (an osmolyte implicated in milk protein synthesis) with increasing Cx26 content. In contrast, physiological taurine concentrations have no effect on Cx26/Cx30 and Cx30/Cx32 channel activity. Such changes in connexin expression and channel composition and their chemical modulation are discussed in relation to the various stages of mammary gland development in the adult mouse.
authors.affiliation: Department of Pharmacology and Physiology, New Jersey Medical School, UMDNJ, Newark, NJ 07103, USA. lockeda@umdnj.edu
authors.forename: Darren
authors.initials: D
authors.lastname: Locke
authors.forename: Susan
authors.initials: S
authors.lastname: Jamieson
authors.forename: Torsten
authors.initials: T
authors.lastname: Stein
authors.forename: Jade
authors.initials: J
authors.lastname: Liu
authors.forename: Malcolm B
authors.initials: MB
authors.lastname: Hodgins
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Harris
authors.forename: Barry
authors.initials: B
authors.lastname: Gusterson
mesh_terms: D000818:Animals; D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D020411:Oligonucleotide Array Sequence Analysis; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013654:Taurine / Q000494:pharmacology; D000097002:Gap Junction beta-1 Protein
chemical_list: D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins; D012333:RNA, Messenger; D013654:Taurine; D000097002:Gap Junction beta-1 Protein; C000607042:GJB2 protein, human; C000607043:Gjb2 protein, mouse; C100629:Gjb6 protein, mouse