Ca2+ signaling in mouse cardiomyocytes with ablated S100A1 protein.

S100A1 is a Ca2+-binding protein expressed at high levels in the myocardium. It is thought to modulate the Ca2+ sensitivity of the sarcoplasmic reticulum (SR) Ca2+ release channels (ryanodine receptors or RyRs) and its expression has been shown to be down regulated in various heart diseases. In this study we used S100A1 knock-out (KO) mice to investigate the consequences of chronic S100A1 deficiency on Ca2+ cycling in ventricular cardiomyocytes.

The role and regulation of friend of GATA-1 (FOG-1) during blood development in the zebrafish.

The nuclear protein FOG-1 binds transcription factor GATA-1 to facilitate erythroid and megakaryocytic maturation. However, little is known about the function of FOG-1 during myeloid and lymphoid development or how FOG-1 expression is regulated in any tissue. We used in situ hybridization, gain- and loss-of-function studies in zebrafish to address these problems.

S100A1-deficient male mice exhibit increased exploratory activity and reduced anxiety-related responses.

S100 proteins comprise a family of Ca(2+) binding proteins of at least 21 members. They are distinctly expressed in a variety of cell types and tissues and are thought to play unique roles, although they share a high degree of sequence homology and expression overlap. S100A1 is prominently expressed in the heart, where it takes part in Ca(2+)-cycling.

Mitoferrin is essential for erythroid iron assimilation.

Iron has a fundamental role in many metabolic processes, including electron transport, deoxyribonucleotide synthesis, oxygen transport and many essential redox reactions involving haemoproteins and Fe-S cluster proteins. Defective iron homeostasis results in either iron deficiency or iron overload. Precise regulation of iron transport in mitochondria is essential for haem biosynthesis, haemoglobin production and Fe-S cluster protein assembly during red cell development.

Vascular endothelial growth factor receptor signaling is required for cardiac valve formation in zebrafish.

Vascular endothelial growth factor-receptors (VEGF-Rs) are pivotal regulators of vascular development, but a specific role for these receptors in the formation of heart valves has not been identified. We took advantage of small molecule inhibitors of VEGF-R signaling and showed that blocking VEGF-R signaling with receptor selective tyrosine kinase inhibitors, PTK 787 and AAC 787, from 17-21 hr post-fertilization (hpf) in zebrafish embryos resulted in a functional and structural defect in cardiac valve development. Regurgitation of blood between the two chambers of the heart, as well as a loss of cell-restricted expression of the valve differentiation markers notch 1b and bone morphogenetic protein-4 (bmp-4), was readily apparent in treated embryos.

Zebrafish slc4a2/ae2 anion exchanger: cDNA cloning, mapping, functional characterization, and localization.

Although the zebrafish has been used increasingly for the study of pronephric kidney development, studies of renal ion transporters and channels of the zebrafish remain few. We report the cDNA cloning and characterization of the AE2 anion exchanger ortholog from zebrafish kidney, slc4a2/ae2. The ae2 gene in linkage group 2 encodes a polypeptide of 1,228 aa exhibiting 64% aa identity with mouse AE2a.

Comparative analysis of estrogenic activity in sewage treatment plant effluents involving three in vitro assays and chemical analysis of steroids.

In this study, we assessed and compared the suitability of three in vitro screening tools for the measurement of estrogenic activity in sewage treatment plant effluents (STPEs). These assays were the yeast estrogen screen (YES), production of zona radiata proteins (ZRPs) in trout hepatocytes, and the induction of reporter gene expression in the transfected rainbow trout gonad cell line RTG-2. Data obtained with the YES were additionally compared with calculated estrogenicity, based on steroid analysis data of the effluents.

Zebrafish: a genetic model for vertebrate organogenesis and human disorders.

Mutations may be tolerated without noticeable effect or may present with a specific phenotype that reveals information about the function of the mutated gene. This information is an inexhaustible source for understanding biology and let us ask particular questions about the molecular mechanisms of development, degeneration and disease. The zebrafish (Danio rerio) has been proven to be instrumental in the genetic analysis of spontaneous and induced mutations and has provided invaluable clues to the elucidation of complex molecular processes in vertebrate biology.

Development of a fish reporter gene system for the assessment of estrogenic compounds and sewage treatment plant effluents.

This study reports on the development and application of a fish-specific estrogen-responsive reporter gene assay. The assay is based on the rainbow trout (Oncorhynchus mykiss) gonad cell line RTG-2 in which an acute estrogenic response is created by cotransfecting cultures with an expression vector containing rainbow trout estrogen receptor a complementary DNA (rtERalpha cDNA) in the presence of an estrogen-dependent reporter plasmid and an estrogen receptor (ER) agonist. In a further approach, RTG-2 cells were stably transfected with the rtERalpha cDNA expression vector, and clones responsive to 17beta-estradiol (E2) were selected.

Effects of long-term nonylphenol exposure on gonadal development and biomarkers of estrogenicity in juvenile rainbow trout Oncorhynchus mykiss.

Environmental pollutants with estrogenic activity including nonylphenol (NP) have the potential to alter gonadal development and reproduction of wild fish. To investigate the estrogenic action of environmentally relevant concentrations of NP, rainbow trout (Oncorhynchus mykiss) were continuously exposed during the embryonic, larval and juvenile life stage to 1.05 and 10.