In zebrafish, three atoh1 genes, atoh1a, atoh1b, and atoh1c, are expressed in overlapping but distinct expression domains in the upper rhombic lip (URL): ptf1a is expressed exclusively in the ventricular zone (VZ). Using transgenic lines expressing fluorescent proteins under the control of the regulatory elements of atoh1a and ptf1a, we traced the lineages of the cerebellar
neurons. The atoh1(+) progenitors gave rise not only to granule cells but also to neurons of the anteroventral rhombencephalon. The ptf1a(+) progenitors generated Purkinje cells. The olig2(+) eurydendroid cells, which are glutamatergic, were derived mostly from ptf1a(+) progenitors in the VZ but some originated from the atoh1(+) progenitors in the URL In the adult cerebellum, atoh1a, atoh1b, and atoh1c are expressed in the molecular layer of the valvula
cerebelli and P005091 solubility dmso TH-302 molecular weight of the medial corpus cerebelli, and ptf1a was detected in the VZ. The proneural gene expression patterns coincided with the sites of proliferating neuronal progenitors in the adult cerebellum. Our data indicate that proneural gene-linked neurogenesis is evolutionarily conserved in the cerebellum among vertebrates, and that the continuously generated neurons help remodel neural circuits in the adult zebrafish cerebellum. (C) 2010 Elsevier Inc. All rights reserved.”
“Insulin-like growth factors (IGFs) SN-38 have been implicated in normal mammalian kidney development. To confirm a role for the lGF system in podocyte and glomerular integrity, we generated a transgenic mouse that expresses a dominant-negative type I IGF receptor (IGF-IR) and determined the structural and functional consequences. Using a 4.25 kb fragment of the murine nephrin promoter, the dominant-negative construct was expressed exclusively
in the kidney, confirmed by Southern blot and RT-PCR analysis. IGF-Ir486(FLAGstop) protein localized specifically to the glomerular podocyte based on FLAG immunohistochemistry and on colocalization with nephrin and podocin. Wild type and transgenic glomeruli expressed both the alpha- and beta-subunits of the endogenous IGF-IR. with normal expression of both nephrin and podocin. Although the animals were viable and phenotypically normal, histological analysis of the kidneys revealed abnormal and small glomeruli with dilated glomerular capillaries and condensed podocyte nuclei, while ultra-structural examination revealed diffuse but segmental podocyte foot process broadening, fusion, and effacement. Explanted glomeruli from transgenic animals demonstrated a significant inhibition of podocyte cell outgrowth when compared to controls. These studies suggest that IGF signaling is essential for maintaining the integrity of the podocyte and that alterations of IGF signaling may play a role in progressive glomerular disease. (c) 2007 Elsevier Ltd. All rights reserved.