Matrix glycoprotein SC1/ECM2 augments B lymphopoiesis

Kenji Oritani, Yuzuru Kanakura, Keisuke Aoyama, Takafumi Yokota, Neal G. Copeland, Debra J. Gilbert, Nancy A. Jenkins, Yoshiaki Tomiyama, Yuji Matsuzawa, Paul W. Kincade

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The extracellular matrix produced by stromal cells plays a critical role in lymphohematopoiesis. It was recently discovered that matrix glycoprotein SC1/ECM2 is a component of that matrix and preliminary evidence suggested that it could contribute to the nurturing environment for B-lymphocyte precursors. A fusion protein prepared from the amino terminal portion of SC1/ECM2 and the constant region of human Ig preferentially bound to pre-B cells. Furthermore, the cloning efficiency of interleukin-7-dependent B-cell precursors was increased in a dose-dependent manner by addition of this fusion protein. We now report the complete cDNA sequence for murine SC1/ECM2 and its localization to the central region of chromosome 5. A fusion protein prepared from the full length of SC1/ECM2 and Ig was found to recognize pre- B cells in a divalent cation-dependent manner, and to augment mitogen- dependent proliferation of mature B cells, as well as the cloning of pre-B cells, but to have no influence on myeloid progenitor cells. Although SC1/ECM2 is normally a secreted protein, we show that it is also capable of augmenting lymphopoiesis when expressed as a transmembrane protein on fibroblasts. Although the C-terminal portion of SC1/ECM2 has sequence homology to osteonectin/SPARC, the unique N-terminal one fifth of the protein was sufficient to augment lymphocyte growth.

Original languageEnglish (US)
Pages (from-to)3404-3413
Number of pages10
Issue number9
StatePublished - 1997

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology


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