Expression of connexin48.5, connexin44.1, and connexin43 during zebrafish ( Danio rerio ) lens development

Kremer

Cell Communication & Adhesion

et al. 2008

Gap junctions are among the most widely distributed cell structures involved in cell-to-cell communication. Recently completed genome sequencing projects including species from all major phyla have demonstrated the existence of three distinct gene families, the connexins, pannexins, and innexins, as molecular building blocks of gap junctional communication. In the present study, the authors have addressed the molecular complexity of gap junction gene expression in the zebrafish retina, a remarkably complex sensory organ built by diverse neuronal subtypes. Using a combination of cDNA library and genomic DNA library screening and/or RACE technology, the authors have cloned, in addition to the four previously reported connexins, seven novel connexins and four pannexin transcripts resembling two pannexin genes. This result demonstrates the presence of two distinct gap junction type gene families and indicates a remarkable molecular and functional diversity of gap junction-mediated coupling in the fish retina.

Section: Introductionsupporting

confidence: 77%

Molecular Diversity of Connexin and Pannexin Genes in the Retina of the ZebrafishDanio rerio

Kremer

Cell Communication & Adhesion

et al. 2008

“…47 In the lens, perp starts to be expressed around 24 hpf and vanishes again during the second day of development, very similar to the dynamics of connexin43 and 44, markers for differentiating lens fiber cells. 48 Similarly, in the gastrointestinal tract, 49,50 pronephric ducts, 51 and cartilage, 52,53 perp expression coincides with cell differentiation. In sum, it appears that in most tissues, the perp gene is expressed during cell differentiation processes, while it is switched off in terminally differentiated cells.…”

Section: Discussionmentioning

confidence: 99%

Perp is required for tissue-specific cell survival during zebrafish development

2004

The tumor suppressor p53 has two alternative effects, causing either cell cycle arrest or apoptosis. These different effects are supposed to be mediated by the transcriptional activation of different target genes. perp, encoding a transmembrane protein of the Pmp22 family, is a transcriptional p53 target exclusively upregulated in apoptotic cells. However, its role during normal development had remained largely unclear. Here, we report the isolation and characterization of a zebrafish perp homolog. Upon overexpression in early zebrafish embryos, perp induces apoptosis. In addition, it contributes to p53-dependent and UVinduced cell death. However, during normal zebrafish development, perp displays a p53-independent and spatially restricted expression in specific cell types and tissues. Antisensemediated loss of Perp function leads to increased apoptosis in perp-expressing cells of the developing skin and notochord. We conclude that, in contrast to its proapoptotic function in stressed cells, Perp plays an antiapoptotic role during normal zebrafish development to regulate tissue-specific cell survival. Cell Death and Differentiation (2005) Keywords: perp; p53; pmp22; apoptosis; cell survival; zebrafish; development Abbreviations: AO, acridine orange; BrdU, 5 0 Bromo-2 0 -desoxyuridine; DNp63, amino-terminally truncated isoform of p63; EST, expressed sequence tag; EVL, enveloping layer; hpf, hours postfertilization; mdm2, mouse double minute 2; MO, morpholino oligonucleotide; RT-PCR, polymerase chain reaction after reverse transcription of RNA; SDS-PAGE, sodiumdodecylsulfate polyacrylamide gel electrophoresis; TAp73, transactivating N-terminally full-length isoform of p73; TUNEL, terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling; UV, ultraviolet; 4 mm, four mismatch control

Journal of Biological Chemistry

“…In this study we demonstrate that in addition to the lens, Cx48.5 is expressed in the embryonic and adult heart, in the early otic vesicles, and adult testes. We have recently reported a detailed description of the Cx48.5 WMISH expression pattern in the developing zebrafish lens (27). Although it is somewhat perplexing that we did not see any Cx48.5 staining in the heart by WMISH at developmental times when the antisense morpholinos disrupted cardiovascular function most severely, as we pointed out in the results section, we feel that the absence a cardiac Cx48.5 signal in these embryos is due to insufficient sensitivity of the technique rather than lack of Cx48.5 expression.…”

Section: Discussionmentioning

confidence: 99%

“…Whole Mount in Situ Hybridization (WMISH) and Whole Mount Immunohistochemistry-WMISH was carried out as previously described (27). The Cx48.5 probe was 775 bp long extending from 612 nucleotides downstream of the start codon to 81 nucleotides downstream of the stop codon, and the cardiac myosin light chain 2 (cmlc2) probe (a generous gift from Dr. Didier Stainier) was about a 1-kb-long fragment from the 3Ј end of the cmlc2 cDNA (29).…”

Section: Methodsmentioning

confidence: 99%

“…In a recent study (27) we showed by RT-PCR that Cx48.5, a zebrafish connexin with extensive sequence similarity to mammalian Cx46, is expressed in the adult lens and presented a detailed whole mount in situ hybridization analysis of Cx43, Cx44.1, and Cx48.5 expression in the embryonic lens. In the present study we describe the isolation and further characterization of Cx48.5.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Connexin 48.5 Is Required for Normal Cardiovascular Function and Lens Development in Zebrafish Embryos

Cheng

Shakespeare

Mui

et al. 2004

Self Cite

Gap junctions are composed of connexin (Cx) proteins and mediate intercellular communication required for many developmental and physiological processes. Here we describe the isolation and characterization of Cx48.5, a zebrafish connexin with the highest sequence identity to mammalian Cx46. Expression analysis showed that Cx48.5 is expressed in the adult and embryonic lens and heart, adult testis, and transiently in the embryonic otic vesicles. Injection of Cx48.5 cRNA into Xenopus oocytes elicited intercellular electrical coupling with voltage sensitivity similar to mammalian Cx46. In single oocytes, Cx48.5 also induced large outward currents on depolarization, consistent with gap-junctional hemichannels. Disruption of Cx48.5 expression in embryos with antisense morpholino oligos (morpholinos) revealed that Cx48.5 has an essential role in the maintenance of lens homeostasis. The morpholino-treated embryos also developed small lenses and eyes as well as severe cardiovascular abnormalities.Gap junctions are clusters of intercellular channels that allow the propagation of small metabolites, signaling molecules, and electrical impulses between adjacent cells. The protein units that make up the gap junction channels in vertebrates are called connexins and are coded for by a multigene family with 20 or more members in mammals (1). Gap junctions play vital roles in the functions of virtually all organs, including the lens and the heart. The evidence to date suggests that distinct sets of connexins may play a role in the development and function of organs like the lens and the heart. Three connexins are expressed in the mammalian lens. Connexin 43 is expressed in the undifferentiated lens epithelium, whereas Cx46 1 and Cx50 are typically considered lens-specific and are predominantly expressed in the lens fiber cells (for review, see Ref.2). Both Cx46 and Cx50 knock-out mice developed cataracts (3-5), and the Cx50 knock-out mice also developed small lenses and small eyes.Four connexins are abundantly expressed in the mammalian heart: Cx43, Cx40, Cx45, and Cx37. Connexin 43 is expressed in the atrial and ventricular working myocardium, Cx40 is found in the atrial working myocardium and the conducting bundle branches and Purkinje fibers, whereas Cx45 is restricted to the atrioventricular conduction system, and Cx37 is restricted to endothelial and endocardial cells (for reviews, see Refs. 6 -8). Mouse knock-out experiments have demonstrated that Cx43, Cx40, and Cx45 are all essential for cardiac development and function. For instance, connexin 43 knock-out mice died neonatally from pulmonary outflow tract obstruction (9). Connexin 40-deficient mice on the other hand exhibited slowed cardiac conduction and a partial atrioventricular block (10, 11). Last, Cx45 knock-out mice died by embryonic day 10 displaying the effects of a conduction block, endocardial cushion defects, and abnormalities of vascular development (12, 13). The Cx37 knock-out mice had no apparent cardiovascular abnormalities (14). Although the expression a...