کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8476253 | 1550612 | 2008 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Unexpected activities of Smad7 in Xenopus mesodermal and neural induction
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
بیولوژی سلول
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Unexpected activities of Smad7 in Xenopus mesodermal and neural induction Unexpected activities of Smad7 in Xenopus mesodermal and neural induction](/preview/png/8476253.png)
چکیده انگلیسی
Neural induction is widely believed to be a direct consequence of inhibition of BMP pathways. Because of conflicting results and interpretations, we have re-examined this issue in Xenopus and chick embryos using the powerful and general TGFβ inhibitor, Smad7, which inhibits both Smad1- (BMP) and Smad2- (Nodal/Activin) mediated pathways. We confirm that Smad7 efficiently inhibits phosphorylation of Smad1 and Smad2. Surprisingly, however, over-expression of Smad7 in Xenopus ventral epidermis induces expression of the dorsal mesodermal markers Chordin and Brachyury. Neural markers are induced, but in a non-cell-autonomous manner and only when Chordin and Brachyury are also induced. Simultaneous inhibition of Smad1 and Smad2 by different approaches does not account for all Smad7 effects, indicating that Smad7 has activities other than inhibition of the TGFβ pathway. We provide evidence that these effects are independent of Wnt, FGF, Hedgehog and retinoid signalling. We also show that these effects are due to elements outside of the MH2 domain of Smad7. Together, these results indicate that BMP inhibition is not sufficient for neural induction even when Nodal/Activin is also blocked, and that Smad7 activity is considerably more complex than had previously been assumed. We suggest that experiments relying on Smad7 as an inhibitor of TGFβ-pathways should be interpreted with considerable caution.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Mechanisms of Development - Volume 125, Issues 5â6, MayâJune 2008, Pages 421-431
Journal: Mechanisms of Development - Volume 125, Issues 5â6, MayâJune 2008, Pages 421-431
نویسندگان
Irene de Almeida, Ana Rolo, Julie Batut, Caroline Hill, Claudio D. Stern, Claudia Linker,