1. TEBs in vivo display reduced apico-basal polarity and extensive intercellular membrane protrusions.
TEBs in vivo display reduced apico-basal polarity and extensive intercellular membrane protrusions. (A) Mammary epithelial ducts are elongated by TEBs, shown here in a light micrograph, with boxes indicating regions that were subsequently imaged by TEM. (B,B′) TEBs contain a fluid-filled lumen with microvilli and tight junctions. (C–F″) Cells within the multilayered region appeared morphologically unpolarized and displayed extensive intercellular protrusions. These protrusions were observed to interdigitate (D) and branch (F″). (G–G″) Cells at the apical or basal most tissue surface were polarized at the tissue boundary but could be unpolarized and irregularly shaped a few microns away. (H) Microlumens within the body cell region had both microvilli and tight junctions. All TEM images are from high pressure frozen, freeze-substituted samples that were pre-fixed with 4% glutaraldehyde. Des, desmosomes; TJ, tight junctions.
Andrew J. Ewald et al. J Cell Sci 2012;125:
© 2012.