Tgfbr2 is required for development of the skull vault.
Transforming growth factor beta (TGFbeta) is known to play important roles in multiple developmental processes. One of the main functions is in skeletal development. Our previous studies demonstrated that loss of Tgfbr2 in Prx1Cre-expressing limb mesenchyme results in defects in the long bones and joints of mice. Here we show that loss of Tgfbr2 also results in defects in the development of the skull vault indicating Tgfbr2 has a critical role in intramembranous bone formation as well as endochondral bone formation. Mutant mice did not survive after birth and demonstrated an open skull. The first signs of skull defects were observed at E14.5 day. Prx1Cre(+)/Tgfbr2(f/f) embryos showed significantly reduced cell proliferation in the developing mesenchyme of the skull by E14.5 day without any detectable alteration in apoptosis suggesting that reduced cell proliferation in Prx1Cre(+)/Tgfbr2(f/f) embryos was at least partially responsible for the defects observed. Immunofluorescent staining showed a significant reduction in the expression of Runx2/Cbfa1 and Osterix/Sp7 in Prx1Cre(+)/Tgfbr2(f/f) embryos suggesting that osteoblast differentiation was also altered in Prx1Cre(+)/Tgfbr2(f/f) embryos. To distinguish between the effects of losing Tgfbr2 on mesenchymal proliferation versus osteoblast differentiation, osteoprogenitor cells from the skulls of Tgfbr2(f/f) embryos were cultured under conditions of high cell density and Tgfbr2 was deleted from the cells using Adeno-Cre virus. RT-PCR analysis showed that the mRNA level of Runx2 and Osterix as well as Dlx5 and Msx2 were down-regulated in Tgfbr2-deleted cultures compared to control cultures indicating that Tgfbr2 regulates osteoblast differentiation independent of regulating proliferation. Together, these results suggest that Tgfbr2 is required for normal development of the skull.
Seo
Hwa-Seon
HS
Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA.
Serra
Rosa
R
D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D050659:Core Binding Factor Alpha 1 Subunit / Q000502:physiology; D046149:Embryo Culture Techniques; D005624:Frontal Bone / Q000002:abnormalities / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D005804:Genes, Lethal; D018398:Homeodomain Proteins / Q000235:genetics; D008648:Mesoderm / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D010006:Osteoblasts / Q000502:physiology; D010012:Osteogenesis / Q000235:genetics* / Q000502:physiology; D010294:Parietal Bone / Q000002:abnormalities / Q000196:embryology*; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000502:physiology
D050659:Core Binding Factor Alpha 1 Subunit; D018398:Homeodomain Proteins; C489936:Prrx1 protein, mouse; D018125:Receptors, Transforming Growth Factor beta; C493716:Runx2 protein, mouse; D000076182:Sp7 Transcription Factor; C479466:Sp7 protein, mouse; D014157:Transcription Factors; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II
Cell. 1997 May 30;89(5):765-71
9182764
Microsc Res Tech. 2001 Feb 15;52(4):374-86
11170296
Development. 1999 Dec;126(24):5611-20
10572038
Cells Tissues Organs. 2009;189(1-4):144-52
18728356
Development. 1997 Jul;124(13):2659-70
9217007
J Biomed Mater Res A. 2007 Dec 1;83(3):770-8
17559111
Development. 2005 Nov;132(22):4937-50
16221730
Cell. 1997 May 30;89(5):755-64
9182763
Anat Embryol (Berl). 2002 Dec;206(1-2):73-83
12478370
J Biol Chem. 2004 Jan 16;279(3):1650-8
14576167
Anat Rec. 1983 May;206(1):61-70
6881551
Development. 2006 Jan;133(2):371-81
16368934
Genesis. 2002 Feb;32(2):73-5
11857781
Mol Cell Biol. 2000 Dec;20(23):8783-92
11073979
J Invest Dermatol. 2002 Feb;118(2):211-5
11841535
Annu Rev Cell Dev Biol. 2000;16:191-220
11031235
Dev Biol. 2004 Dec 1;276(1):124-42
15531369
Arch Biochem Biophys. 2008 May 15;473(2):98-105
18331818
Bioessays. 2000 Feb;22(2):138-47
10655033
Genesis. 2002 Jun;33(2):77-80
12112875
Development. 1994 Jan;120(1):165-75
8119124
Dev Cell. 2002 Apr;2(4):389-406
11970890
Birth Defects Res C Embryo Today. 2003 Nov;69(4):333-51
14745974
Eur J Biochem. 2000 Dec;267(24):6982-8
11106407
J Cell Biochem. 2005 Jun 1;95(3):518-28
15786511
Dev Biol. 2007 Apr 15;304(2):860-74
17335796
Genes Dev. 1994 Jan;8(2):133-46
8299934
Teratology. 1980 Dec;22(3):299-301
6165088
Development. 2003 Nov;130(21):5269-80
12975342
Genes Dev. 2002 May 1;16(9):1089-101
12000792
Development. 1999 Sep;126(17):3795-809
10433909
Stain Technol. 1981 Sep;56(5):271-3
6171056
Development. 2000 Apr;127(8):1671-9
10725243
Cell. 2002 Jan 11;108(1):17-29
11792318
Nat Genet. 2000 Apr;24(4):391-5
10742104
Development. 2003 Dec;130(24):6131-42
14597577
Dev Biol. 2007 Oct 15;310(2):304-16
17822689
Mech Dev. 2007 Sep-Oct;124(9-10):729-45
17693062
J Biol Chem. 2005 Nov 11;280(45):37400-7
16131487
Dev Biol. 2002 Jan 1;241(1):106-16
11784098