Claudin-5 is Restricted to the Tight Junction Region of Uterine Epithelial Cells in the Uterus of Pregnant/Gravid Squamate Reptiles

Authors

  • Joanna M. Biazik,

    Corresponding author
    1. School of Medical Sciences (Anatomy and Histology) and Bosch Institute, The University of Sydney, NSW, Australia
    2. School of Biological Sciences, The University of Sydney, NSW, Australia
    • School of Medical Science (Anatomy and Histology), Anderson Stuart Building F13, The University of Sydney, NSW 2006, Australia
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  • Michael B. Thompson,

    1. School of Biological Sciences, The University of Sydney, NSW, Australia
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  • Christopher R. Murphy

    1. School of Medical Sciences (Anatomy and Histology) and Bosch Institute, The University of Sydney, NSW, Australia
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Abstract

Claudin-5, a tight junctional protein associated with ion and size selectivity, has been found in the uterus of skinks. This study has generated critical information about the molecular assembly of the tight junction at various stages of the reproductive cycle in the skink uterus. Recent studies looking at tight junctional proteins found occludin expression in the tight junction region of uterine epithelial cells in the skink uterus; however, occludin did not disclose any further information about the ions and size of ions permeating across the paracellular pathway. A ∼22-kDa claudin-5 band was detected in the uterus of the skinks present in this study and immunohistochemistry revealed that claudin-5 redistributes to the tight junction region of the lateral plasma membrane of uterine epithelial cells in late stage pregnancy/gravidity. This finding indicates that the tight junction becomes more assembled to precisely regulate ion and solute permeation in late stage pregnancy/gravidity. Claudin-5 with its functional role as a molecular sieve due to the formation of ion and size selective pores suggests that permeation of ions smaller than 0.8 kDa are restricted when claudin-5 is redistributed to the tight junction region of the later plasma membrane. This report is the first description of the molecular mechanisms that may be involved in regulating nutrient provision in the reptilian uterus. Anat Rec, 291:547–556, 2008. © 2008 Wiley-Liss, Inc.

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