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Full-Text Articles in Life Sciences
A Dynamic Gli Code Interprets Hh Signals To Regulate Induction, Patterning, And Endocrine Cell Specification In The Zebrafish Pituitary, Christine A. Devine, Jennifer L. Sorogna, Burcu Guner, Marcey Osgood, Meng-Chieh Shen, Rolf O. Karlstrom
A Dynamic Gli Code Interprets Hh Signals To Regulate Induction, Patterning, And Endocrine Cell Specification In The Zebrafish Pituitary, Christine A. Devine, Jennifer L. Sorogna, Burcu Guner, Marcey Osgood, Meng-Chieh Shen, Rolf O. Karlstrom
Biology Department Faculty Publication Series
Hedgehog (Hh) signaling is necessary for the induction and functional patterning of the pituitary placode, however the mechanisms by which Hh signals are interpreted by placodal cells are unknown. Here we show distinct temporal requirements for Hh signaling in endocrine cell differentiation and describe a dynamic Gli transcriptional response code that interprets these Hh signals within the developing adenohypophysis. Gli1 is required for the differentiation of selected endocrine cell types and acts as the major activator of Hh-mediated pituitary induction, while Gli2a and Gli2b contribute more minor activator functions. Intriguingly, this Gli response code changes as development proceeds. Gli1 continues …
Cloning Of Zebrafish Nkx6.2 And A Comprehensive Analysis Of The Conserved Transcriptional Response To Hedgehog/Gli Signaling In The Zebrafish Neural Tube, Burcu Guner, Rolf O. Karlstrom
Cloning Of Zebrafish Nkx6.2 And A Comprehensive Analysis Of The Conserved Transcriptional Response To Hedgehog/Gli Signaling In The Zebrafish Neural Tube, Burcu Guner, Rolf O. Karlstrom
Biology Department Faculty Publication Series
Sonic Hedgehog (Shh) signaling helps pattern the vertebrate neural tube, in part by regulating the dorsal/ventral expression of a number of homeodomain containing transcription factors. These Hh responsive genes have been divided into two classes, with Class II genes being activated by Hh signaling and Class I genes being repressed by Hh signaling. While the transcriptional response to varying Hh levels is well defined in chick and mouse, it is only partially described in zebrafish, despite the fact that zebrafish has emerged as a powerful genetic system for the study of neural patterning. To better characterize the Hh response in …
Hedgehog Regulated Slit Expression Determines Commissure And Glial Cell Position In The Zebrafish Forebrain, Michael J.F. Barresi, Lara D. Hutson, Chi Bin Chien, Rolf O. Karlstrom
Hedgehog Regulated Slit Expression Determines Commissure And Glial Cell Position In The Zebrafish Forebrain, Michael J.F. Barresi, Lara D. Hutson, Chi Bin Chien, Rolf O. Karlstrom
Biology Department Faculty Publication Series
Three major axon pathways cross the midline of the vertebrate forebrain early in embryonic development: the postoptic commissure (POC), the anterior commissure (AC) and the optic nerve. We show that a small population of Gfap+astroglia spans the midline of the zebrafish forebrain in the position of, and prior to, commissural and retinal axon crossing. These glial `bridges' form in regions devoid of the guidance molecules slit2 and slit3,although a subset of these glial cells express slit1a. We show that Hh signaling is required for commissure formation, glial bridge formation, and the restricted expression of the guidance molecules slit1a …
Genetic Analysis Of Zebrafish Gli1 And Gli2 Reveals Divergent Requirements For Gli Genes In Vertebrate Development, Rolf O. Karlstrom, Oksana V. Tyurina, Atsushi Kawakami, Noriyuki Nishioka, William S. Talbot, Hiroshi Sasaki, Alexander F. Schier
Genetic Analysis Of Zebrafish Gli1 And Gli2 Reveals Divergent Requirements For Gli Genes In Vertebrate Development, Rolf O. Karlstrom, Oksana V. Tyurina, Atsushi Kawakami, Noriyuki Nishioka, William S. Talbot, Hiroshi Sasaki, Alexander F. Schier
Biology Department Faculty Publication Series
Gli proteins regulate the transcription of Hedgehog (Hh) target genes. Genetic studies in mouse have shown that Gli1 is not essential for embryogenesis, whereas Gli2 acts as an activator of Hh target genes. In contrast, misexpression studies in Xenopus and cultured cells have suggested that Gli1 can act as an activator of Hh-regulated genes, whereas Gli2 might function as a repressor of a subset of Hh targets. To clarify the roles of gli genes during vertebrate development, we have analyzed the requirements for gli1 and gli2 during zebrafish embryogenesis. We report that detour (dtr) mutations encode loss-of-function alleles …