Type IIA procollagen containing the cysteine-rich amino propeptide is deposited in the extracellular matrix of prechondrogenic tissue and binds to TGF-beta1 and BMP-2.
Type IIA procollagen containing the cysteine-rich amino propeptide is deposited in the extracellular matrix of prechondrogenic tissue and binds to TGF-beta1 and BMP-2.
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DOI：
10.1083/jcb.144.5.1069
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发表时间：
1999-03-08
期刊：
影响因子：
--
通讯作者：
Sandell LJ
中科院分区：
文献类型：
--
作者：
Zhu Y;Oganesian A;Keene DR;Sandell LJ
II型前胶原以两种剪接形式表达。一种形式，IIB型，由软骨细胞合成，是软骨的主要细胞外基质成分。另一种形式，IIA型，在NH 2-前肽中含有额外的69个氨基酸的富含半胱氨酸的结构域，并由软骨形成间充质和软骨膜合成。我们假设IIA型前胶原的额外蛋白结构域在软骨形成中起作用。本研究旨在确定IIA型NH 2-前肽的定位及其在软骨形成过程中的功能。使用IIA型前胶原分子的三个结构域的抗体的免疫荧光组织化学被用来本地化的NH 2-前肽，纤维结构域，和COOH-前肽的IIA型前胶原分子在软骨形成过程中在发育中的人长骨（阶段XXI）。在软骨形成之前，软骨祖细胞合成IIA型前胶原并沉积在细胞外基质中。免疫电子显微镜显示IIA型前胶原原纤维标记的抗体NH 2-前肽在~ 70 nm的间隔表明，NH 2-前肽仍然附着在细胞外基质中的胶原分子。随着分化的进行，细胞将IIA型前胶原的合成转换为IIB型前胶原，并且新合成的IIB型胶原将IIA型前胶原置换到区域间基质中。为了启动对IIA型前胶原的功能的研究，测试了重组NH 2-前肽与已知参与软骨形成的各种生长因子之间的结合。固相结合试验显示与bFGF或IGF-1无反应，然而，观察到与TGF-β1和BMP-2结合，两者均已知诱导软骨内骨形成。BMP-2，而不是IGF-1，与IIA型NH 2-前肽共免疫沉淀。来自培养基的重组IIA型NH 2-前肽和IIA型前胶原与BMP-2共免疫沉淀，而重组IIB型NH 2-前肽和所有其他形式的II型前胶原和成熟胶原不与BMP-2反应。两者合计，这些结果表明，IIA型前胶原的NH 2-前肽可以在软骨形成组织中骨形态发生蛋白的细胞外基质分布中发挥作用。
Type II procollagen is expressed as two splice forms. One form, type IIB, is synthesized by chondrocytes and is the major extracellular matrix component of cartilage. The other form, type IIA, contains an additional 69 amino acid cysteine-rich domain in the NH2-propeptide and is synthesized by chondrogenic mesenchyme and perichondrium. We have hypothesized that the additional protein domain of type IIA procollagen plays a role in chondrogenesis. The present study was designed to determine the localization of the type IIA NH2-propeptide and its function during chondrogenesis. Immunofluorescence histochemistry using antibodies to three domains of the type IIA procollagen molecule was used to localize the NH2-propeptide, fibrillar domain, and COOH-propeptides of the type IIA procollagen molecule during chondrogenesis in a developing human long bone (stage XXI). Before chondrogenesis, type IIA procollagen was synthesized by chondroprogenitor cells and deposited in the extracellular matrix. Immunoelectron microscopy revealed type IIA procollagen fibrils labeled with antibodies to NH2-propeptide at ∼70 nm interval suggesting that the NH2-propeptide remains attached to the collagen molecule in the extracellular matrix. As differentiation proceeds, the cells switch synthesis from type IIA to IIB procollagen, and the newly synthesized type IIB collagen displaces the type IIA procollagen into the interterritorial matrix. To initiate studies on the function of type IIA procollagen, binding was tested between recombinant NH2-propeptide and various growth factors known to be involved in chondrogenesis. A solid phase binding assay showed no reaction with bFGF or IGF-1, however, binding was observed with TGF-β1 and BMP-2, both known to induce endochondral bone formation. BMP-2, but not IGF-1, coimmunoprecipitated with type IIA NH2-propeptide. Recombinant type IIA NH2-propeptide and type IIA procollagen from media coimmunoprecipitated with BMP-2 while recombinant type IIB NH2-propeptide and all other forms of type II procollagens and mature collagen did not react with BMP-2. Taken together, these results suggest that the NH2-propeptide of type IIA procollagen could function in the extracellular matrix distribution of bone morphogenetic proteins in chondrogenic tissue.
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影响因子：
3.4
作者：
HIRAOKA, Y;SEDAT, JW;AGARD, DA
通讯作者：
AGARD, DA
影响因子：
10.5
作者：
FRANCOIS, V;SOLLOWAY, M;BIER, E
通讯作者：
BIER, E
影响因子：
5.6
作者：
EIKENBERRY, EF;CHILDS, B;BRODSKY, B
通讯作者：
BRODSKY, B
影响因子：
64.5
作者：
Marques, G;Musacchio, M;OConnor, MB
通讯作者：
OConnor, MB
影响因子：
3.2
作者：
Oganesian, A;Zhu, Y;Sandell, LJ
通讯作者：
Sandell, LJ