Bone morphogenetic proteins (BMPs) are members of the
transforming growth factor-b (TGFb) superfamily of extracellular
signalling molecules, which play multiple roles in
the regulation of growth, differentiation and apoptosis of
numerous cell types. Several BMPs have recently been
implicated as autocrine/paracrine regulators of ovarian follicle
development (Elvin et al. 1999, Shimasaki et al.
1999). For instance, BMP-4 and -7 are expressed by theca
cells in the rat (Shimasaki et al. 1999), BMP-3 is expressed
in human granulosa-lutein cells (Jaatinen et al. 1996),
BMP-6 is expressed by mouse oocytes (Elvin et al. 2000)
and BMP-15/growth differentiation factor (GDF)-9B and
GDF-9 are expressed exclusively by oocytes (McGrath
et al. 1995, Bodensteiner et al. 1999, Jaatinen et al. 1999,
Elvin et al. 2000, McNatty et al. 2001). Furthermore, rat
granulosa cells and oocytes express mRNA for the BMP
receptor (BMPR) types IA, IB and II throughout follicle
development (Shimasaki et al. 1999) whilst sheep granulosa
cells and oocytes were recently shown to express
BMPRIB and BMPRII (Wilson et al. 2001).
Like other members of the TGFb superfamily, BMPs signal
by binding to and forming heteromeric complexes
with two types of serine/threonine kinase receptor (type-I
and type-II) on the cell surface (Massague & Chen 2000,
Miyazono et al. 2000, Miyazawa et al. 2002). The type-II
receptor transphosphorylates a type-I receptor, which in
turn activates transcriptional regulators called Smads,
Bone morphogenetic proteins (BMPs) are members of thetransforming growth factor-b (TGFb) superfamily of extracellularsignalling molecules, which play multiple roles inthe regulation of growth, differentiation and apoptosis ofnumerous cell types. Several BMPs have recently beenimplicated as autocrine/paracrine regulators of ovarian follicledevelopment (Elvin et al. 1999, Shimasaki et al.1999). For instance, BMP-4 and -7 are expressed by thecacells in the rat (Shimasaki et al. 1999), BMP-3 is expressedin human granulosa-lutein cells (Jaatinen et al. 1996),BMP-6 is expressed by mouse oocytes (Elvin et al. 2000)and BMP-15/growth differentiation factor (GDF)-9B andGDF-9 are expressed exclusively by oocytes (McGrathet al. 1995, Bodensteiner et al. 1999, Jaatinen et al. 1999,Elvin et al. 2000, McNatty et al. 2001). Furthermore, ratgranulosa cells and oocytes express mRNA for the BMPreceptor (BMPR) types IA, IB and II throughout follicledevelopment (Shimasaki et al. 1999) whilst sheep granulosacells and oocytes were recently shown to expressBMPRIB and BMPRII (Wilson et al. 2001).Like other members of the TGFb superfamily, BMPs signalby binding to and forming heteromeric complexeswith two types of serine/threonine kinase receptor (type-Iand type-II) on the cell surface (Massague & Chen 2000,Miyazono et al. 2000, Miyazawa et al. 2002). The type-IIreceptor transphosphorylates a type-I receptor, which inturn activates transcriptional regulators called Smads,
การแปล กรุณารอสักครู่..
