Mammalian mitochondrial DNA (mtDNA) is a small, maternally inherited genome that codes for 13 essential proteins in the respiratory chain. Mature oocytes contain more than 150 000 copies of mtDNA, at least an order magnitude greater number most somatic cells, but sperm only approximately 100 copies. Mitochondrial oxidative phosphorylation has been suggested to be important determinant oocyte quality and motility; however, functional significance high mtDNA copy oocytes, low sperm, remains...

Abstract Background Understanding the dynamic cellular behaviors and underlying molecular mechanisms that drive morphogenesis is an ongoing challenge in biology. Live imaging provides necessary methodology to unravel synergistic stereotypical cell events shape embryo. Genetically-encoded reporters represent essential tool for live imaging. Reporter strains can be engineered by placing cis -regulatory elements of interest direct expression a desired reporter gene. In case canonical Wnt...

Hepatocyte nuclear factors (HNFs) are a heterogeneous class of evolutionarily conserved transcription that required for cellular differentiation and metabolism. Mutations in HNF-1α HNF-4α genes impair insulin secretion cause type 2 diabetes. Regulation HNF-4/HNF-1 expression by HNF-3α HNF-3β was studied embryoid bodies which one or both alleles were inactivated. positively regulated the HNF-4α/HNF-1α their downstream targets, implicating role also necessary . In contrast, acts as negative...

ABSTRACT During early embryogenesis, the transcription factor HNF3β is expressed in visceral and definitive endoderm, node, notochord floorplate. A targeted mutation gene results lack of a node notochord. Furthermore, failure proper primitive streak elongation. To address whether required we have used tetraploid embryo-ES cell aggregations to generate chimeric mouse embryos with wild-type endoderm homozygous mutant embryonic ectoderm or vice versa. Replacing rescued elongation and,...

Recent studies have demonstrated that the LIM homeodomain transcription factor Islet1 (Isl1) marks pluripotent cardiovascular progenitor cells and is required for proliferation, survival, migration of recently defined second heart field progenitors. Factors are upstream Isl1 in progenitors not yet been defined. Here we demonstrate β-catenin expression cardiac progenitors, directly regulating promoter. Ablation β- catenin Isl1-expressing disrupts multiple aspects cardiogenesis, resulting...

The otic placode, the anlagen of inner ear, develops from an ectodermal field characterized by expression transcription factor Pax2. Previous fate mapping studies suggest that these Pax2(+) cells will give rise to both placode tissue and epidermis, but signals divide into placodal epidermal territories are unknown. We report Wnt signaling is normally activated in a subset cells, conditional inactivation beta-catenin causes expansion markers at expense placode. Conversely, activation...

Successful implantation relies on precisely orchestrated and reciprocal signaling between the implanting blastocyst receptive uterus. We have examined role of Wnt/β-catenin pathway during process demonstrate that this is activated two distinct stages. first transiently in circular smooth muscle forming a banding pattern activity within uterus early day 4. Subsequently, activation restricted to luminal epithelium at prospective site implantation. Activation both sites requires presence...

Abstract The neuroepithelial layer of the developing eyecup contains multipotential precursor cells that give rise to all neurons and one glial cell type present in adult retina. Patterning within retinal neuroepithelium is regulated by intrinsic as well extrinsic mechanisms. Although identity some signaling molecules regulate development known, function many others, especially members Wnt family, has yet be characterized context development. We undertook a comprehensive situ hybridization...

Abstract β‐Catenin signaling has been shown to be involved in triggering axis formation several organisms, including Xenopus and zebrafish. Genetic analysis demonstrated that the Wnt/β‐catenin pathway is also mouse, since a targeted deletion of β‐catenin results embryos have block anterior–posterior formation, fail initiate gastrulation, do not form mesoderm. However, because ubiquitously expressed, precise time cell types which this active during early embryonic development remain unknown....

The canonical WNT signaling pathway plays a crucial role in patterning of the embryo during development, but little is known about specific developmental events which are under control. To understand more how orchestrates mammalian organogenesis, we studied beta-catenin-mediated kidneys mice bearing beta-catenin-responsive TCF/betaGal reporter transgene. In metanephric kidney, intense was evident epithelia branching ureteric bud and nephrogenic mesenchyme its transition into renal tubules....

The role of the Wnt[b]/beta-catenin-dependent pathway (canonical Wnt pathway) in context retinal development and homeostasis is largely unknown. This study was undertaken to characterize activation canonical its relevance cell type populations developing adult retina.Tissue from TCF/Lef-LacZ (T-cell-specific transcription factor/lymphoid enhancer-binding factor) transgenic mice used for monitoring pathway. Lithium (Li(+)) treatment applied induce ectopic reporter gene explants. Gene...

Studies of the c-myc promoter have shown that efficient transcription initiation at P2 start site as well block to elongation require presence ME1a1 protein binding upstream TATA box. Following fractionation by size exclusion chromatography, three protein-ME1a1 DNA complexes, a, b, and c, were detected electrophoretic mobility shift assay. A cDNA encoding a present in complex c was isolated screening an expression library with probe. This found encode human homolog Drosophila Cut homeodomain...

In the embryonic kidney, progenitors in metanephric mesenchyme differentiate into specialized renal epithelia a defined sequence characterized by formation of cellular aggregates, conversion polarized and segmentation along proximal-distal axis. This is reiterated throughout development to generate nephrons. Here, we identify global transcriptional programs associated with epithelial differentiation utilizing an organ culture model rat mesenchymal differentiation, which recapitulates...

Specification and early patterning of the vertebrate heart are dependent on both canonical noncanonical wingless (Wnt) signal pathways. However, impact each Wnt pathway later stages myocardial development differentiation remains controversial. Here, we report that components conduit expressed in developing postnatal heart, yet canonical/β-catenin activity is restricted to nonmyocardial regions. Subsequently, observed (Wnt11) enhanced myocyte while preventing stabilization β-catenin protein,...

Homeodomain-containing proteins are believed to function as sequence-specific DNA binding proteins, regulating gene expression. Specificity of sequence recognition is conferred by the homeodomain acting either alone or in conjunction with other conserved domains case for Pou domain and Paired proteins. The recent isolation cDNAs encoding mammalian homologues Drosophila Cut protein has revealed that 72-amino acid Repeats evolution. We have investigated biochemical activity human expressing...

Implantation of mammalian embryos depends on differentiation the blastocyst to a competent state and uterine endometrium receptive state. Communication between uterus ensures that these changes are temporally coordinated. Although considerable evidence indicates induces expression numerous genes in tissue, potential signaling mechanisms have yet be identified. Moreover, whereas surge maternal estradiol occurring Day 4 pregnancy mouse is critically required for many peri-implantation changes,...

A block to elongation of transcription has been shown occur within the first exon human and murine c-myc genes. The extent this was found vary with physiological state cells, indicating that modulation transcriptional can serve control expression gene. To determine which sequences are required in cis for block, we generated a series constructs containing various portions 5'-flanking 1 sequences. We established populations HeLa CV-1 cells stably transfected these constructs. start sites were...

Preterm birth is the single leading cause of perinatal mortality in developed countries, affecting approximately 12% pregnancies and accounting for 75% neonatal loss United States. Despite prevalence severity premature delivery, causes mechanisms that underlie spontaneous idiopathic preterm remain unknown. Our inability to elucidate these fundamental has been attributed a poor understanding signaling pathways associated with induction parturition lack suitable animal models available...

Abstract NR5A2, also known as liver receptor homologue 1 (LRH‐1) and fetoprotein transcription factor (FTF), is an orphan nuclear involved in the regulation of cholesterol metabolism steroidogenesis adult. NR5A2 was shown to be expressed during early mouse embryogenesis. Consistent with its expression pattern, a targeted disruption this gene leads embryonic lethality around gastrulation period. To characterize phenotype resulting from loss function, we undertook morphological marker analyses...

The Wnt pathway is an essential signaling cascade that regulates multiple processes in developing and adult tissues, including differentiation, cellular survival, stem cell proliferation. authors recently demonstrated altered expression of genes during photoreceptor death rd1 mice, suggesting involvement for the disease process. In this study, investigated role retinal degeneration.The reporter mouse line Tcf-LacZ was crossed with degeneration beta-galactosidase used to localize death. To...

The polyomavirus origin for DNA replication comprises at least two essential, but functionally distinct, cis-acting components. One of these, the core, is required only replication. It includes binding sites large T antigen and bidirectional other component both transcription represented by redundant regions, alpha beta, which are elements enhancer. Whereas either enhancer element will activate replication, to constitute a functional transcription. To identify sequences that make up each...

NR5A2 is an orphan nuclear receptor involved in cholesterol metabolism and embryogenesis. The high level of expression the ovary its involvement regulation steroidogenic gene also suggest a role for this transcription factor female reproductive function. In vivo evidence fertility, however, still lacking. order to address possibility, we used Nr5a2+/- mice demonstrate that heterozygosity null mutation Nr5a2 leads decreased fertility females. Our results indicate although display normal...