Xenopus crescent encoding a Frizzled-like domain is expressed in the Spemann organizer and pronephros

نویسندگان

  • Mikihito Shibata
  • Hirofumi Ono
  • Hiroki Hikasa
  • Jun Shinga
  • Masanori Taira
چکیده

The Spemann organizer can be subdivided into head- and trunk-inducing tissues along the anteroposterior axis (Mangold, 1933. Naturwiisenschaften 43, 761-766; Spemann, 1931. Wilhelm Roux Arch. Entwicklungsmech. Org. 123, 389-517). Recent studies have suggested that head formation is brought about by repression of both Wnt and BMP signalling (Glinka et al., 1998. Nature 391, 357-362; Glinka et al., 1997. Nature 389, 517-519). Several Wnt inhibitors secreted from the head organizer region have been identified in Xenopus, such as Cerberus (Bouwmeester et al., 1996. Nature 382, 595-601), Frzb-1 (Leyns et al., 1997. Cell 88, 747-756; Lin et al., 1997. Proc. Natl. Acad. Sci. USA 94, 11196-11200), and Dkk-1 (Glinka et al., 1998. Nature 391, 357-362), supporting this two-inhibitor model. To isolate genes expressed in the head organizer, we screened a prechordal plate cDNA library by sequencing and expression pattern, and isolated the Xenopus ortholog of chick crescent encoding a Frizzled-like domain that is related to Wnt-binding regions of the Frizzled-family proteins. Expression of Xenopus crescent was first detected in the Spemann organizer region at the early gastrula stage and later in prechordal plate cells lining the boundary of mesoderm and ectoderm layers and in the anterior endoderm. At tailbud stages, the expression in the endomesoderm region was diminished, while expression in the pronephros became detectable. In animal cap assays, crescent gene was synergistically upregulated by coexpression of Xlim1, Ldb1, and Siamois, but not by Activin treatment.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Frzb, a Secreted Protein Expressed in the Spemann Organizer, Binds and Inhibits Wnt-8

We isolated a Xenopus homolog of Frzb, a newly described protein containing an amino-terminal Frizzled motif. It dorsalized Xenopus embryos and was expressed in the Spemann organizer during early gastrulation. Unlike Frizzled proteins, endogenous Frzb was soluble. Frzb was secretable and could act across cell boundaries. In several functional assays, Frzb antagonized Xwnt-8, a proposed ventrali...

متن کامل

Frzb-1 Is a Secreted Antagonist of Wnt Signaling Expressed in the Spemann Organizer

Frzb-1 is a secreted protein containing a domain similar to the putative Wnt-binding region of the frizzled family of transmembrane receptors. Frzb-1 is widely expressed in adult mammalian tissues. In the Xenopus gastrula, it is expressed and regulated as a typical Spemann organizer component. Injection of frzb-1 mRNA blocks expression of XMyoD mRNA and leads to embryos with enlarged heads and ...

متن کامل

Frizzled-8 is expressed in the Spemann organizer and plays a role in early morphogenesis.

Wnts are secreted signaling molecules implicated in a large number of developmental processes. Frizzled proteins have been identified as likely receptors for Wnt ligands in vertebrates and invertebrates, but a functional role for vertebrate frizzleds has not yet been defined. To assess the endogenous role of frizzled proteins during vertebrate development, we have identified and characterized a...

متن کامل

A role for Xenopus Frizzled 8 in dorsal development

The establishment of cell and tissue polarity during animal development often requires signaling by Wnts, extracellular signaling polypeptides. Transmembrane receptors of the Frizzled family are implicated in the transduction of Wnt signals in responding cells. Xfz8 is a novel cDNA encoding a Xenopus homologue of mouse Frizzled 8. Xfz8 transcripts are expressed zygotically in the organizer at t...

متن کامل

Overexpression of the secreted factor Mig30 expressed in the Spemann organizer impairs morphogenetic movements during Xenopus gastrulation

The Spemann organizer secretes several antagonists of growth factors during gastrulation. We describe a novel secreted protein, Mig30, which is expressed in the anterior endomesoderm of the Spemann organizer. Mixer-inducible gene 30 (Mig30) was isolated as a target of Mixer, a homeobox gene required for endoderm development. The Mig30 gene encodes a secreted protein containing a cysteine-rich d...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • Mechanisms of Development

دوره 96  شماره 

صفحات  -

تاریخ انتشار 2000