Quantitative analysis of Hedgehog gradient formation using an inducible expression system

Background  

The Hedgehog (Hh) family of secreted growth factors are morphogens that act in development to direct growth and patterning. Mutations in human Hh and other Hh pathway components have been linked to human diseases. Analysis of Hh distribution during development indicates that cholesterol modification and receptor mediated endocytosis affect the range of Hh signaling and the cellular localization of Hh.     

Lactation failure in Src knockout mice is due to impaired secretory activation

Background  

Mammary gland development culminates in lactation and is orchestrated by numerous stimuli and signaling pathways. The Src family of nonreceptor tyrosine kinases plays a pivotal role in cell signaling. In order to determine if Src plays a role in mammary gland development we have examined mammary gland development and function during pregnancy and lactation in mice in which expression of Src has been eliminated.     

Analysis of inhibitor of apoptosis protein family expression during mammary gland development

Background  

Inhibitors-of-Apoptosis-Proteins (IAPs) are an evolutionarily conserved family of proteins capable of regulating several facets of apoptosis. IAPs are frequently dysregulated in cancer, but their role in the regulation of apoptosis during developmental processes is not fully understood. Here we examined the expression of IAPs during the post-natal development of the mouse mammary gland, which is a tissue that exhibits a profound induction of apoptosis during involution.     

Wnt5 signaling in vertebrate pancreas development

Background  

Signaling by the Wnt family of secreted glycoproteins through their receptors, the frizzled (Fz) family of seven-pass transmembrane proteins, is critical for numerous cell fate and tissue polarity decisions during development.     

Systemic endopolyploidy in <Emphasis Type="Italic">Spathoglottis plicata</Emphasis> (Orchidaceae) development

Background  

Endopolyploidy is developmentally regulated. Presence of endopolyploidy as a result of endoreduplication has been characterized in insects, mammals and plants. The family Orchidaceae is the largest among the flowering plants. Many of the members of the orchid family are commercially micropropagated. Very little has been done to characterize the ploidy variation in different tissues of the orchid plants during development.     

Genetic analysis of the two zebrafish patched homologues identifies novel roles for the hedgehog signaling pathway

Background  

Aberrant activation of the Hedgehog (Hh) signaling pathway in different organisms has shown the importance of this family of morphogens during development. Genetic screens in zebrafish have assigned specific roles for Hh in proliferation, differentiation and patterning, but mainly as a result of a loss of its activity. We attempted to fully activate the Hh pathway by removing both receptors for the Hh proteins, called Patched1 and 2, which are functioning as negative regulators in this pathway.     

Generation of FGF reporter transgenic zebrafish and their utility in chemical screens

Background  

Fibroblast Growth Factors (FGFs) represent a large family of secreted proteins that are required for proper development and physiological processes. Mutations in mouse and zebrafish FGFs result in abnormal embryogenesis and lethality. A key to understanding the precise role for these factors is to determine their spatial and temporal activity during embryogenesis.     

Gap junctions in the ovary of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>: localization of innexins 1, 2, 3 and 4 and evidence for intercellular communication via innexin-2 containing channels

Background  

In the Drosophila ovary, germ-line and soma cells are interconnected via gap junctions. The main gap-junction proteins in invertebrates are members of the innexin family. In order to reveal the role that innexins play in cell-cell communication during oogenesis, we investigated the localization of innexins 1, 2, 3 and 4 using immunohistochemistry, and analyzed follicle development following channel blockade.     

Developmental expression of survivin during embryonic submandibular salivary gland development

Background  

The regulation of programmed cell death is critical to developmental homeostasis and normal morphogenesis of embryonic tissues. Survivin, a member of the inhibitors of apoptosis protein (IAP) family primarily expressed in embryonic cells, is both an anti-apoptosis and a pro-survival factor. Since our previous studies have demonstrated the importance of apoptosis during embryonic submandibular salivary gland (SMG) development, we postulated that survivin is a likely mediator of SMG epithelial cell survival.     

Expression of Lhx6 in the adult and developing mouse retina

PurposeTo investigate the expression patterns of LIM Homeobox 6 (Lhx6) in the adult and developing mouse retina.MethodsThe Lhx6-GFP knock-in allele was used to activate constitutive expression of a GFP reporter in Lhx6 expressing cells. Double labeling with GFP and retinal markers in the mouse retina at postnatal day 56 (P56) was performed to identify the cell types expressing Lhx6. To determine the neuronal cell types that express Lhx6, double labeling with GFP and various retinal markers was employed in the differentiating retina at P7 and P15.ResultsGFP + Lhx6 lineage cells were determined in Brn3a + retinal ganglion cells (RGCs), ChAT + amacrine cells (ACs), and Islet-class LIM-homeodomain 1 (Isl1+) ACs in the mouse retina at P56. In the ganglion cell layer (GCL), Lhx6 was expressed in Brn3a + RGCs but not Brn3b + RGCs at P15. Moreover, in the inner nuclear layer (INL), Lhx6 was not expressed in Bhlhb5+ ACs at P15. However, Lhx6 was weakly expressed in Glyt1+ ACs and Pax6+ ACs, and strongly expressed in Isl1+ and ChAT + ACs at P15.ConclusionLhx6 was expressed in RGCs and ACs in both the adult and developing mouse retina.