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Localization of the novel Xin protein to the adherens junction complex in cardiac and skeletal muscle during development
Author(s) -
Sinn Haley W.,
Balsamo Janne,
Lilien Jack,
Lin Jim J.C.
Publication year - 2002
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.10131
Subject(s) - adherens junction , biology , myogenesis , microbiology and biotechnology , vinculin , sarcomere , skeletal muscle , myocyte , sarcolemma , intercalated disc , actin , cardiac muscle , heart development , colocalization , embryonic stem cell , anatomy , embryonic heart , cadherin , cell , gap junction , genetics , signal transduction , focal adhesion , intracellular , gene
Previously, we demonstrated that chick embryos treated with antisense oligonucleotides against a striated muscle‐specific Xin exhibit abnormal cardiac morphogenesis (Wang et al. [1999] Development 126:1281–1294); therefore, we surmised a role for Xin in cardiac development. Herein, we examine the developmental expression of Xin through immunofluorescent staining of whole‐mount mouse embryos and frozen heart sections. Xin expression is first observed within the heart tube of embryonic day 8.0 (E8.0) mice, exhibiting a peripheral localization within the cardiomyocytes. Colocalization of Xin with both β‐catenin and N‐cadherin is observed throughout embryogenesis and into adulthood. Additionally, Xin is found associated with β‐catenin within the N‐cadherin complex in embryonic chick hearts by coimmunoprecipitation. Xin is detected earlier than vinculin in the developing heart and colocalizes with vinculin at the intercalated disc but not at the sarcolemma within embryonic and postnatal hearts. At E10.0, Xin is also detected in the developing somites and later in the myotendon junction of skeletal muscle but not within the costameric regions of muscle. In cultured C2C12 myotubes, the Xin protein is found in many speckled and filamentous structures, coincident with tropomyosin in the stress fibers. Additionally, Xin is enriched in the regions of cell–cell contacts. These data demonstrate that Xin is one of the components at the adherens junction of cardiac muscle, and its counterpart in skeletal muscle, the myotendon junction. Furthermore, temporal and spatial expressions of Xin in relation to intercalated disc proteins and thin filament proteins suggest roles for Xin in the formation of cell–cell contacts and possibly in myofibrillogenesis. © 2002 Wiley‐Liss, Inc.