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Evaluation of Mammary Gland Development and Function in Mouse Models
08:51

Evaluation of Mammary Gland Development and Function in Mouse Models

Published on: July 21, 2011

Two proto-oncogenes implicated in mammary carcinogenesis, int-1 and int-2, are independently regulated during mouse

A Jakobovits, G M Shackleford, H E Varmus

    Proceedings of the National Academy of Sciences of the United States of America
    |October 1, 1986
    PubMed

    Insights

    Proto-oncogenes int-1 and int-2 are activated in mammary tumors. Researchers investigated their normal expression patterns in developing mice, finding distinct temporal and spatial activity during embryogenesis and in adult tissues.

    Area of Science:

    • Developmental Biology
    • Oncogenesis
    • Molecular Biology

    Background:

    • The int-1 and int-2 genes were identified as proto-oncogenes activated by mouse mammary tumor virus (MMTV) proviral insertions in mammary carcinomas.
    • Previous studies indicated these genes were not expressed in normal adult mouse tissues, suggesting a role in development or specific cell types.

    Purpose of the Study:

    • To investigate the expression patterns of int-1 and int-2 proto-oncogenes during mouse embryogenesis.
    • To determine if int-1 and int-2 are expressed in cultured teratocarcinoma cells.

    Main Methods:

    • Analysis of int-1 and int-2 RNA expression in mouse embryos at various developmental stages (peri-implantation, mid-gestation, late gestation).
    • Examination of RNA from cultured teratocarcinoma cells.
    • Detection of RNA in normal adult mouse tissues and postpuberal testes.

    Main Results:

    • Int-1 RNA was detected specifically during mid-gestation (days 8-13) and in adult testes.
    • Four species of int-2 RNA were found in peri-implantation embryos and teratocarcinoma cells, with high abundance in primitive endodermal lineage derivatives.
    • Int-2 RNA was not detected during mid- or late gestation or in any tested normal adult tissues.

    Conclusions:

    • The proto-oncogenes int-1 and int-2 exhibit distinct temporal and spatial expression patterns during mouse development and in adult tissues.
    • These findings highlight differential gene regulation of proto-oncogenes activated by similar mechanisms in carcinogenesis.

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