Identification and developmental expression of TJP family and the function of TJP3 in zebrafish

Abstract

<P>TIGHT JUNCTIONS (TJ) ARE IMPORTANT COMPONENTS OF EPITHELIAL TISSUES WHERE THEY ARE REQUIRED FOR BARRIER FUNCTIONS, EPITHELIAL CELL POLARITY AND SIGNALING EVENTS IN RESPONSE TO CELL-CELL CONTACT. THE ZONA OCCLUDENS (ZO) OR TIGHT JUNCTION PROTEINS (TJP) LINK TJ INTEGRAL MEMBRANE PROTEINS TO THE ACTIN CYTOSKELETON AND ALSO SERVE AS SCAFFOLDS FOR SIGNALING PROTEINS. </P><P>IN THIS STUDY I REPORT THE IDENTIFICATION OF FIVE TIGHT JUNCTION PROTEINS (TJP) IN TELEOSTS AND I DESCRIBE THEIR EXPRESSION PATTERNS DURING ZEBRAFISH DEVELOPMENT. INDIVIDUAL TJPS SHOW A TISSUE SPECIFIC EXPRESSION DURING EARLY ORGANOGENESIS OF THE ZEBRAFISH EMBRYO. </P><P>I SHOW THAT TJP3/ZO-3 IS A COMPONENT OF TJS PRESENT IN THE ENVELOPING CELL LAYER (EVL) OF ZEBRAFISH EMBRYOS. SILENCING TJP3/ZO-3 USING MORPHOLINOS LEADS TO A DISRUPTION OF TJ ARCHITECTURE AND TO THE LOSS OF EPIDERMAL BARRIER FUNCTION. THUS TJP3 IS REQUIRED FOR THE FUNCTION OF THE EVL AS A DIFFUSION BARRIER IN THE EARLY ZEBRAFISH EMBRYO. </P>