XTrR-I is a TGFbeta receptor and overexpression of truncated form of the receptor inhibits axis formation and dorsalising activity.
We have previously cloned a type I serine/threonine kinase receptor from Xenopus, namely XTrR-I. We show here that XTrR-I is able to bind and mediate the activity of TGFbeta1, but is unable to mediate response to activin or BMP-4. We have made a truncated receptor construct that can act as a dominant negative mutant receptor, and this can block the activity of TGFbeta2 but not that of activin. Overexpression of either the full-length or truncated receptor has a drastic effect on mesoderm differentiation. The truncated receptor inhibits expression of notochord and muscle in mesodermalised animal caps, while the full-length receptor greatly increases the amount of notochord. In addition, the truncated receptor blocks the axis duplicating activity of both siamois and Xwnt8. We conclude that XTrR-I is involved in mediating a dorsalising activity important for mesoderm differentiation.
Mahony
D
D
Wellcome/CRC Institute, Tennis Court Road, Cambridge, CB2 1QR, UK.
Weis
F M
FM
Massagué
J
J
Gurdon
J B
JB
D028341:Activins; D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D017353:Gene Deletion; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D007265:Inhibins / Q000378:metabolism; D008648:Mesoderm / Q000737:chemistry / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000196:embryology; D009154:Mutation; D009672:Notochord / Q000187:drug effects / Q000196:embryology; D012333:RNA, Messenger / Q000235:genetics / Q000494:pharmacology; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014981:Xenopus; D029867:Xenopus Proteins
D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; C094515:XTrR-I receptor; D029867:Xenopus Proteins; C525812:bmp4 protein, Xenopus; D028341:Activins; D007265:Inhibins