... and regulation of hyaluronate density and swelling are unknown. Here, we identify the transcription factor Lmx1b as a positive transcriptional regulator of hyaluronan, Versican, and chondroitin synthesis genes crucial for canal morphogenesis. We show that Versican regulates hyaluronan density through its protein...

...Endika Haro; Billy A. Watson; Jennifer M. Feenstra; Luke Tegeler; Charmaine U. Pira; Subburaman Mohan; Kerby C. Oberg Lmx1b is a homeodomain transcription factor responsible for limb dorsalization. Despite striking double-ventral (loss-of-function) and double-dorsal (gain-of-function) limb...

... the coordination of musculoskeletal patterning during mouse limb development. Using both conditional gain- and loss-of-function approaches, we selectively deleted or activated the LIM-homeodomain transcription factor Lmx1b in skeletal progenitors using a Sox9-Cre knock-in allele. As Lmx1b is both necessary...

..., it is unknown how these signaling interactions are processed in the responding cells. We have found that distinct LIM homeodomain transcription factors, encoded by the LIM homeobox(LIM-HD) genes Lhx2, Lhx9 and Lmx1b integrate the signaling events that link limb patterning and outgrowth along all three axes...

... factor En1( Ahn et al., 2001 ; Logan et al., 1997 ; Pizette and Niswander, 2001 ). In the dorsal mesoderm, the transcription factor Lmx1b (Lmx1 in the chick)responds to Wnt7a signals and specifies the dorsal mesenchymal structures( Chen et al., 1998 ; Riddle et al., 1995 ; Vogel et al., 1995...

...). However, transcriptional regulation of these secreted factors during development remains to be elucidated. Here we show that the LIM homeobox gene Lmx1b is expressed in the anterior embryo as early as E7.5 and its expression becomes progressively restricted to the isthmus at E9.0. Analysis of gene...

..., in these limbs, the expression of Bmp2, Bmp4 and Bmp7 , and of the Bmp target genes Msx1,Msx2 and gremlin, is expanded in the mesenchyme. Furthermore, we found that the expression of Lmx1b , a gene exclusively expressed in the dorsal limb mesenchyme and involved in dorsoventral patterning, is reduced upon loss...

... that the LIM homeobox transcription factor Lmx1b is expressed within the chick IsO, where it is sufficient to maintain expression of the secreted factor wnt1 . In this paper, we show that zebrafish express two Lmx1b orthologs, lmx1b.1 and lmx1b.2 , in the rostral IsO, and demonstrate that these genes...

... report that the differentiation and migration of the superficial dorsal horn neurons are regulated by the LIM homeobox gene Lmx1b , and its downstream targets Rnx and Drg11 , two transcription factors implicated in the development of dorsal horn circuitry. An analysis of Lmx1b mutants shows that Lmx1b...

.... Involvement of Wnt1 in the isthmic organizing activity was suggested by analysis of Wnt1 knockout mice. But its role in isthmic organizing activity is still obscure. Recently, it has been shown that Lmx1b is expressed in the isthmic region and that it may occupy higher hierarchical position in the gene...

.... * Author for correspondence (e-mail: [email protected] ) 06 11 2000 21 12 2000 © 2001 by Company of Biologists 2001 Engrailed Lmx1b Wnt1 Gbx2 Otx2 Pax5 Pax6 Fibroblast growth factor Organizer Mouse Fgf8 , which is expressed at the junction...

... which eventually defines the mesencephalic/ metencephalic boundary (MMB). Here we report that the transcription factor Lmx1b is expressed and functions in a distinct region of the IsO. Lmx1b expression is maintained by the glycoprotein Fgf8 , a signal capable of mediating IsO signaling. Lmx1b, in turn...

... of the broadened mutant AER and the distal border of an ectopic Lmx1b expression domain. Analysis of En1/Wnt7a double mutants demonstrates that the dorsalizing gene Wnt7a is required for the formation of the ectopic AERs in En1 mutants and for ectopic expression of Lmx1b in the ventral mesenchyme. We suggest...