Fig. 7
Csmd1 KO mothers have increased offspring mortality related to maternal nursing defects. a Scatterplot depicting number of pups surviving the neonatal period versus live births, stratified by maternal Csmd1 genotype. Points that lie along the dashed line (slope = 1) represent litters with no neonatal deaths. Maternal Csmd1 genotype is significantly associated with surviving litter size (10.5% vs. 50.0% survival; Poisson regression p-value = 7.93 × 10−7). Points deviate slightly from whole numbers for ease of visualization. b Immunofluorescence shows CSMD1 expression in bifurcating mammary ducts and bulbous terminal end buds. CSMD1 is expressed on both lumenal epithelial cells and myoepithelial cells throughout different stages of adult life. Expression is lowest at puberty and increases during pregnancy, with the highest intensity during involution. Scale bars = 50 μm. c Higher magnification image of CSMD1 expression in a myoepithelial cell (dashed lines, left) surrounding an alveolus during lactation and stromal cells (right). Scale bars = 50 μm. d Whole-mount mammary glands of wildtype and knockout littermates show reduced epithelial network density (square brackets) in knockouts. Scale bars = 5 mm. e Knockout ducts demonstrate reduced number lateral branches (arrowheads). Scale bars = 500 μm. f Image analysis in age-matched wildtype vs. knockout nongravid nulliparous adult mammary ducts. Knockout females have significantly reduced number of branch points along the ducts (JD, two-tailed t-test p-value < 0.05) and reduced number of end segments (EPD, two-tailed t-test p-value < 0.01). VPA = percent area occupied by ducts. JD = branchpoint density per mm. TVL = sum of Euclidean distances among adjacent branchpoints. AVL = average Euclidean distance between adjacent branch points. EPD = number of duct end points normalized by total vessel length. Center line = median; hinges = upper and lower quartiles; whiskers = 1.5 × interquartile range. g C3 and CSMD1 colocalize in mammary. Immunofluorescence shows abundant C3 signal within mammary ducts with empty lumina (left) and ducts with cells in the lumen (middle). C3 signal is also present in some CSMD1-positive stromal cells (right). Scale bars = 20 μm. Source data are provided as a Source Data file
