Expression of two novel eph-related receptor protein tyrosine kinases in mammary gland development and carcinogenesis

Oncogene. 1994 May;9(5):1461-7.


To investigate the involvement of protein tyrosine kinases (PTKs) in the growth control of mammary epithelial cells, we have used PCR based cloning to identify PTKs expressed in a mouse mammary epithelial cell line. This approach led to the isolation of two receptor PTKs of the eph-related subfamily; myk-1, a novel member expressed predominantly in lung, heart and mammary gland and myk-2, a close relative of the human eck gene. Northern blot analysis of RNA from mouse mammary glands at different stages of development revealed that myk-1 and myk-2 expression is induced at puberty and differentially regulated during the estrus cycle. myk-1 and myk-2 expression was down-regulated during the pregnancy induced differentiation of the mammary gland. Over-expression of myk-1 and myk-2 was found in the undifferentiated and invasive mammary tumors of transgenic mice expressing the Ha-ras oncogene. In contrast, no elevated expression of either gene could be detected in the well differentiated and non-metastatic mammary tumors of c-myc expressing transgenic mice. These results indicate that myk-1 and myk-2 expression is induced during the proliferation of the mammary gland and down-regulated by its differentiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Mammary Glands, Animal / chemistry*
  • Mammary Neoplasms, Animal / chemistry*
  • Mice
  • Molecular Sequence Data
  • Neoplasm Proteins / chemistry*
  • Neoplasm Proteins / genetics
  • Protein-Tyrosine Kinases / chemistry*
  • Protein-Tyrosine Kinases / genetics
  • Receptor Protein-Tyrosine Kinases / chemistry*
  • Receptor Protein-Tyrosine Kinases / genetics
  • Receptor, EphA2
  • Receptor, EphB4*
  • Tumor Cells, Cultured


  • Neoplasm Proteins
  • Ephb4 protein, mouse
  • Protein-Tyrosine Kinases
  • Receptor Protein-Tyrosine Kinases
  • Receptor, EphA2
  • Receptor, EphB4

Associated data

  • GENBANK/U06834