Expression patterns of cartilage collagens and Sox9 during mouse heart development

Otto Rahkonen*, Mikko Savontaus, Eltyeb Abdelwahid, Eero Vuorio, Eero Jokinen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


A majority of congenital heart defects are due to abnormal development of the valves and membranous septa, i.e., connective tissue components of the heart. During development, an interesting feature of cardiac connective tissue is transient expression of collagens typical for cartilage. To better understand the role of these collagens in the heart, we have performed a systematic study on the temporospatial expression of type II and IX collagen isoforms during mouse heart development employing northern hybridization and RNase protection assay. The mRNAs for α1(II) and α1(IX) collagens were expressed transiently between embryonic days 10.5 and 14.5 in embryonic mouse heart. RNase protection assays revealed that for both transcripts the embryonic ("prechondrogenic") variants of the alternatively spliced mRNA isoforms dominated. Immunohistochemistry demonstrated that type IIA collagen and Sox9, its key transcriptional regulator, were expressed in the epithelial-mesenchymal areas of the developing heart, with partially overlapping patterns particularly in valvular and septal regions. In addition, Sox9 expression was detected widely in the developing heart. These observations support the hypothesis that cartilage collagens, especially the long isoform of type II collagen, participate in the morphogenesis of cardiac valves and septa.

Original languageEnglish (US)
Pages (from-to)103-110
Number of pages8
JournalHistochemistry and Cell Biology
Issue number2
StatePublished - Aug 1 2003


  • Development
  • Extracellular matrix
  • Heart
  • Molecular biology
  • Mouse

ASJC Scopus subject areas

  • Histology
  • Molecular Biology
  • Medical Laboratory Technology
  • Cell Biology


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