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LACTATING MOUSE MAMMARY GLAND EXPRESSES SECRETED MGAM WHICH ENABLES UNWEANED SUCKLING PUP STARCH DIGESTION
Author(s) -
Lee Nichols Buford,
DiazSotomayor Maricela,
Avery Stephen E,
Hadsell Darrel L,
Yan Like,
Hamaker Bruce R,
QuezadaCalvillo Roberto
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1074.3
Subject(s) - exon , microbiology and biotechnology , chemistry , mammary gland , endocrinology , biology , medicine , gene , biochemistry , genetics , cancer , breast cancer
All starch digesting activities are reported absent in suckling mice by jejunal mucosal enzyme assay, imunohistochemistry or Western blots. We confirmed that there was no maltase activity or brush border staining with Mgam antibodies at 13d and that these were detected at 25d only in WT. Last year we reported that at 13 d both Mgam null and WT suckling mice can digest amylase treated 13 C‐starch derived α‐limit dextrins (LDx) to increase blood 13 C glucose paradoxically in 13d Mgam null suckling mice lumenal contents were stained by specific Mgam antibodies. Objective Test lactating mouse mammary glands for Mgam and Si gene expression. Methods RNA was extracted from the mammary gland of 10 different strains of WT 30d pp lactating mice. After RT, the cDNA was amplified for Mouse Si (amplicons for exons 1 to 6 or exons 16 to 18) and Mgam (amplicons for exons 1 to 7 or exons 3 to 7). Results Only the Mgam Exon 3 to 7 primers produced 516 bp bands on the Gel. Conclusion we suggest that maltase activity is secreted in mouse milk which enables unweaned pup starch digestion well before brush border bound enzyme development. Splicoforms of the Mgam message, lacking the membrane binding exon 2 coding region, in lactating mouse mammary tissue suggest synthesis of a soluble enzyme activity. This was confirmed by the expression of the exon 2 deleted Mgam message in lactating mammary glands of 10 different mouse strains.