Extracellular matrix protein fibulin-2 is expressed in the embryonic endocardial cushion tissue and is a prominent component of valves in adult heart

Dev Biol. 1995 Jan;167(1):18-26. doi: 10.1006/dbio.1995.1003.


Fibulins-1 and -2 are two recently characterized extracellular matrix proteins of a novel protein family. They are found in many tissues in the adult stage, but several differences in their expression patterns were noted in cultured cells and adult tissues. Fibulin-1 is particularly well expressed in the endocardial cushion tissue (ECT) during embryogenesis and we therefore compared the expression patterns of fibulin-1 and -2 in the developing mouse heart. Antibodies against mouse fibulin-1 and -2 were used in immunofluorescence, and the expression of mRNAs were studied with synthetic oligonucleotides by in situ hybridization. A striking codistribution of fibulin-1 and -2 was seen at all stages of the development of the endocardial cushion tissue. Fibulin-2 was found to be a more specific marker for the embryonic ECT than fibulin-1, which was also transiently expressed in cardiac muscle. Immunofluorescence showed that the fibulins remained expressed in valves of the heart in the adult stage. The results suggest a role of the two fibulins in the development of the ECT and in the maintenance of the tensile strength of the cardiac valves.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Blotting, Northern
  • Calcium-Binding Proteins / analysis*
  • Calcium-Binding Proteins / genetics
  • Extracellular Matrix Proteins / analysis*
  • Extracellular Matrix Proteins / genetics
  • Female
  • Heart / embryology*
  • Heart Valves / chemistry*
  • Mice
  • Molecular Sequence Data
  • Pregnancy
  • RNA, Messenger / analysis
  • Rabbits


  • Calcium-Binding Proteins
  • Extracellular Matrix Proteins
  • RNA, Messenger
  • fibulin 2