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The mammary gland life cycle is exemplified by massive, physiologically dictated changes in cell number and composition, architecture, and functionality. These drastic upheavals, by necessity, also involve the mammary endothelium, which undergoes angiogenic expansion during pregnancy and lactation followed by ordered regression during involution. In this(More)
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,(More)
The activated human Ha-ras oncogene was subjected to the control of the promoter region of the murine whey acidic protein (Wap) gene, which is expressed in mammary epithelial cells in response to lactogenic hormones. The Wap-ras gene was stably introduced into the mouse germ line of five transgenic mice (one male and four females). Wap-ras expression was(More)
BACKGROUND Axl, a member of a family of receptor tyrosine kinases characterized by an extracellular domain resembling cell adhesion molecules and an intracellular conserved tyrosine kinase domain has been reported to induce cell proliferation and transformation. In mice, axl is expressed in the normal mammary gland and over-expressed in aggressive mammary(More)
The methylation-sensitive restriction enzymes Hha I and Hpa II were used to analyze the methylation pattern of four Xenopus laevis genes in DNA of embryos, of erythrocytes, and of untreated and estrogen-treated hepatocytes. Within these four genes all sites tested are fully modified in embryonic DNA. However, the adult beta 1-globin gene is unmethylated in(More)
We report the fate of different derivatives of the vitellogenin genes after injection into fertilized eggs of Xenopus. We injected a constructed minigene as well as a 5' fragment of the A2 vitellogenin gene. The minigene survives in embryogenesis much better than the 5' A2 fragment and is retained more frequently and at a higher level in frog tissues. The(More)
By using the polymerase chain reaction with degenerate oligonucleotides based on highly conserved motifs held in common between all members of the protein tyrosine kinase (PTK) family, a PTK-related sequence was isolated from murine peritoneal macrophage cDNA. Full-length clones have been isolated that encompass the entire coding region of the mRNA, and the(More)
The susceptibility of the mammary epithelium to neoplastic transformation is linked to the exposure to estrogen during the estrous cycle. The effects of the estrous cycle on the mouse mammary gland have been investigated by analyzing 3H-thymidine incorporation, milk protein gene expression and DNA fragmentation. We found that the mammary epithelium(More)
Using degenerate oligos corresponding to two highly conserved motifs within the protein kinase catalytic domain and a PCR-based cloning strategy, we have isolated a cDNA fragment encoding a new member of the Ser/Thr (serine/threonine) family of protein kinases. Expression analysis revealed that the fragment recognized two transcripts (1.6 and 1.4 kb)(More)
The acquisition of invasive properties is a crucial event during carcinogenesis, determining the clinical outcome. The mammary gland at puberty provides an ideal model for investigating the induction and control of invasive growth. During this growth phase, the mammary epithelium participates in a normal, hormonally controlled invasive penetration into the(More)