Journal of Cell Science & Therapy
Open Access
ISSN: 2157-7013
+44 1300 500008
ISSN: 2157-7013
+44 1300 500008
Lisa M Domke and Werner W Franke
German Cancer Research Center, Germany
Scientific Tracks Abstracts: J Cell Sci Ther
Mature Seminiferous Tubules (STs) of mammalian testes comprise the Sertoli cells and germ cells and are tightly surrounded by a special peritubular cell wall. Using biochemical, immune-cytochemical and electron microscopical methods, we have determined that STs differ from all other epithelia by the absence of cytokeratin Intermediate Filaments (IFs) but are rich in vimentin IFs, do not contain major epithelial marker structures and molecules such as desmosomes or E-cadherinbased adherens junctions (AJs) but contain exclusively N-cadherin-based AJs. In Sertoli cells, we have found two new junction structures: (1) N-cadherin-based area adherens which often represent even very large areas connecting Sertoli cells with each other or with germ cells and (2) special AJs arranged in closely and regularly spaced rows of tight junction-like structures and associated with 5-8 nm wide cytoplasm-to-cytoplasm channels (cribelliform junctions). The seminiferous tubule cells are attached to the peritubular wall by a well-developed basal lamina but lack hemidesmosomes and hemidesmosomal marker molecules. The peritubular wall is a stack system of layers of Extracellular Matrix (ECM) structures alternating with monolayers of very flat â�?�?Lamellar Smooth Muscle Cellsâ�? (LSMCs). These LSMCs represent differentiated Smooth Muscle Cells (SMCs; positive for smooth muscle �?±-actin, the corresponding myosin light and heavy chains, �?±-actinin, tropomyosin, smoothelin, desmin, vimentin, filamin, talin, dystrophin, caldesmon, calponin and protein SM22�?±). The cells are laterally connected often in overlapping protrusions by AJs containing cadherin-11 as the predominant cadherin and also P-cadherin and rarely N-cadherin, anchored in cytoplasmic plaques containing �?²-catenin, proteins p120 and p0071, plakoglobin and protein myozap. LSMCs also contain typical SMC structures such as dense bodies, plasma membrane-associated focal adhesions and caveolae. Thus, we conclude that these LSMCs represent a specific SMC type and not just myoid cells or myofibroblasts as stated in the literature.
Lisa M Domke is pursuing her PhD in the Helmholtz Group for Cell Biology of Professor Werner W Franke at German Cancer Research Center, DKFZ, Germany. Her thesis is on the molecular and ultrastructural characterization of cell-cell junctions and cytoskeletons in the tubuli seminiferi and their encasing contractile peritubular wall smooth muscle system of diverse mammalian species to improve current methods of molecular diagnostics.
Email:l.domke@dkfz.de