%0 Journal Article
%T The Predominant Proteins that React to the MC-20 Estrogen Receptor Alpha Antibody Differ in Molecular Weight between the Mammary Gland and Uterus in the Mouse and Rat
%A Aliccia Bollig-Fischer
%A Archana Thakur
%A Jiusheng Wu
%A Yuan Sun
%J International Journal of Biomedical Science
%D 2012
%I 
%X There are many estrogen receptor ¦Á (ER¦Á) antibodies available but few of them target a rodent ER¦Á. Using the MC-20 antibody raised against the C-terminus of mouse ER¦Á, we show in this communication that in the mammary gland of female mice and rats, the wild type (wt) ER¦Á was detected on immunoblots as a dominant protein only during lactation, and the protein was lactating specific as it migrated slightly faster than the 67-kD wt ER¦Á in the uterus, likely due to a different phosphorylation status. In contrast, in the nulliparous, pregnant, involuting and involuted mammary glands, the dominant protein recognized by MC-20 was about 61-kD, which is dubbed herein as ¡°MC-20 reactive protein¡± or MC20RP in abbreviation as its identity is unknown. Our results showed that it was not derived from proteolysis or de-phosphorylation of the 67-kD ER¦Á and was unlikely to be translated from an ER¦Á mRNA variant. Ovariectomy decreased the lactating specific wt ER¦Á but increased the 61-kD MC20RP in the mammary tumors from MMTV-c-myc transgenic mice but these two proteins in the uterus were unaffected. The 61-kD MC20RP was decreased in the mammary tumors, compared with proliferating mammary glands, in estrogen-treated ACI rats. These results suggest that while the lactating specific wt ER¦Á alone or together with the MC20RP may sustain lactation, the MC20RP may support proliferation of the mammary gland and some mammary tumors.
%K estrogen receptor alpha
%K mammary gland
%K breast cancer
%K uterus
%U http://www.ijbs.org/User/ContentFullTextFrame.aspx?VolumeNO=8&StartPage=51