Zebrafish cypher is important for somite formation and heart development

Abstract

Mammalian CYPHER (Oracle, KIA0613), a member of the PDZ-LIM family of proteins (Enigma/LMP-1, ENH, ZASP/Cypher, RIL, ALP, and CLP-36), has been associated with cardiac and muscular myopathies. Targeted deletion of Cypher in mice is neonatal lethal possibly caused by myopathies. To further investigate the role of cypher in development, we have cloned the zebrafish orthologue. We present here the gene, domain structure, and expression pattern of zebrafish cypher during development. Cypher was not present as a maternal mRNA and was absent during early development. Cypher mRNA was first detected at the 3-somite stage in adaxial somites, and as somites matured, cypher expression gradually enveloped the whole somite. Later, cypher expression was also found in the heart, in head and jaw musculature, and in the brain. We further identified 13 alternative spliced forms of cypher from zebrafish heart and skeletal muscle tissue, among them a very short form containing the PDZ domain but lacking the ZM (ZASP-like) motif and the LIM domains. Targeted gene knock-down experiments using cypher antisense morpholinos led to severe defects, including truncation of the embryo, deformation of somites, dilatation of the pericardium, and thinning of the ventricular wall. The phenotype could be rescued by a cypher form, which contains the PDZ domain and the ZM motif, but lacks all three LIM domains. These findings indicate that a PDZ domain protein is important for normal somite formation and in normal heart development. Treatment of zebrafish embryos with cyclopamine, which disrupts hedgehog signaling, abolished cypher expression in 9 somite and 15-somite stage embryos. Taken together, our data suggest that cypher may play a role downstream of sonic hedgehog, in a late stage of somite development, when slow muscle fibers differentiate and migrate from the adaxial cells.

“Z”eroing in on the Role of Cypher in Striated Muscle Function, Signaling, and Human Disease

“…These observations were supported by morpholino knockdown of cypher in zebrafish, which also resulted in cardiac dilation and marked ventricular wall thinning, which are features associated with dilated cardiomyopathy (DCM) (Van der Meer et al 2006). Unlike in mouse, a role for Cypher in sarcomerogenesis was suggested in zebrafish studies (Van der Meer et al 2006); however, it remains to be determined if this was due to species differences or the potential redundancy of other Enigma family members at early stages of mouse somite development.…”

“…These include ZASP-1, -2, -3, -4, -5, -6, which are analogous to mouse Cypher 2s, 1s, 3s, 2c, 1c, and 3c (Vatta et al 2003). On the other hand, zebrafish cypher contains 18 exons and gives rise to at least 13 spice variants, only two of which have counterparts in mouse (Cypher 2s and Cypher 2c) (Van der Meer et al 2006). Based on the large number of splice variants identified in zebrafish, it was suggested that other splice variants of cypher may be expressed in other species (Van der Meer et al 2006).…”

CHAP is a newly identified Z-disc protein essential for heart and skeletal muscle function

“…For example, Cypher (also known as ZASP/oracle) (Faulkner et al, 1999;Passier et al, 2000;Zhou et al, 1999) knockout mice display severe congenital myopathy and early postnatal death, demonstrating the necessity for Z-disc integrity in contracting muscle (Zhou et al, 2001). In zebrafish, knockdown of cypher leads to severe somite and heart defects during development (van der Meer et al, 2006). MLP-null mice by contrast, display normal heart and skeletal muscle development but dilated cardiomyopathy occurs postnatally (Arber et al, 1994).…”

Myofibrillar Myopathies and the Z-Disk Associated Proteins

“…As its name suggests the ZASP mRNA is extensively spliced to result in multiple ZASP isoforms, a feature conserved in all species examined with four isoforms in worms [183], 12 isoforms in flies [184][185][186], 13 in zebrafish [187], and six in mice and humans [11,188] (Figure 4). In mice and humans the isoforms have been characterised according to their length and their expression in the heart or skeletal muscle.…”