Carp, a Cardiac Ankyrin-Repeated Protein, and Its New Homologue, Arpp, Are Differentially Expressed in Heart, Skeletal Muscle, and Rhabdomyosarcomas

Abstract

Arpp, a protein containing an ankyrin repeat domain, PEST sequence, and proline-rich region, is a novel ankyrin-repeated protein highly homologous to Carp, which is proposed to be the putative genetic marker for cardiac hypertrophy. In this study, we comparatively analyzed expression of Arpp and Carp protein in skeletal and cardiac muscles and rhabdomyosarcomas (RMSs). In adult skeletal muscle, Arpp was preferentially expressed in the nucleus and cytoplasm of type I fibers, whereas Carp was barely detectable in skeletal muscle. On the other hand, in adult cardiac muscle, interestingly, Arpp was expressed in ventricles mostly, whereas Carp was expressed throughout the atrium and ventricle. Furthermore, although Carp was identified in fetal heart at 11 developmental weeks, Arpp was very low or undetectable in these fetal hearts. These results suggest that Arpp and Carp are differentially expressed and function in both skeletal and cardiac muscle of fetus and adult. We found that Arpp expression was induced during the differentiation of C2C12 cells in vitro, suggesting that Arpp-expression may be associated with the differentiation stage during myogenesis. Both Arpp and Carp were found to be expressed in all of the RMS cases studied. Because the expression patterns of Arpp in RMS were different from those of muscle actin or desmin, Arpp may be detectable in RMS cases that do not express other existing RMS markers.

ARPP protein is selectively expressed in renal oncocytoma, but rarely in renal cell carcinomas

“…Consistent with our previous data obtained using rabbit polyclonal Ab, 3,5 ARPP was found to be highly expressed in skeletal muscle (data not shown). In addition, we found unexpectedly that ARPP was expressed in part of the renal tubule (Figure 2a).…”

“…1 Unexpectedly, ARPP was found to be expressed at a high level in almost all rhabdomyosarcomas. 3,4 On the other hand, in normal tissues, we found that ARPP was preferentially expressed in skeletal and cardiac muscle. 1,3 Moreover, ARPP was abandunt in mouse denervated gastrocnemius muscles, 5 whereas the biological function of ARPP is largely unknown.…”

“…3,4 On the other hand, in normal tissues, we found that ARPP was preferentially expressed in skeletal and cardiac muscle. 1,3 Moreover, ARPP was abandunt in mouse denervated gastrocnemius muscles, 5 whereas the biological function of ARPP is largely unknown. In the present study, we found that ARPP was expressed in part of the distal tubule of the kidney, and also expressed specifically in renal oncocytoma, a benign tumor of the kidney.…”

“…After incubation in blocking reagent (DAKO) for 10 min, the sections were incubated for 60 min at 601C with rabbit anti-ARPP polyclonal antibody, whose specificity for ARPP has been characterized in detail previously. 3 Subsequently, they were washed in 1 Â TBS containing 0.1% BSA and 0.1% Tween 20, and then incubated with goat anti-rabbit IgG antibody conjugated with gold particles 15 nm in diameter (Amersham Bioscience) for 30 min at 601C. After washing in TBS containing 0.1% BSA and 0.1% Tween 20, the sections were counterstained with uranyl acetate and citrate lead in a similar way to the routine procedure.…”

Cardiac-Restricted Ankyrin-Repeated Protein Is Differentially Induced in Duchenne and Congenital Muscular Dystrophy

“…Coexpression of CARP and YB-1 has been shown to repress the transcriptional target of YB-1, MLC-2v, which is required for the maintenance of cardiac contractility and ventricular chamber morphogenesis (Nguyen-Tran et al, 1999). However, our group and another group recently reported that CARP was localized mainly in the cytoplasm as well as in the nucleus of fetal and adult heart (Bang et al, 2001;Ishiguro et al, 2002). Furthermore, we showed in this study that CARP is localized in the sarcomeric I-Z-I areas of regenerating skeletal muscle.…”