HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bolander, F. F. Articles by Blackstone, M. E. Search for Related Content PubMed PubMed Citation Articles by Bolander, F. F. Articles by Blackstone, M. E.

The envelope protein, gp52, of the mouse mammary tumour virus (MMTV) binds to a cell-surface receptor as a first step in infection. A protein with characteristics of this receptor was measured on freshly isolated cells using, as ligand, ¹²⁵I-labelled gp52 purified from C3H/HeN mice. The gp52-binding protein was found in all mouse tissues examined, but was present at highest concentrations in the mammary gland and spleen where it reached 4.2±0.3 (S.E.M.) pmol/mg protein; the dissociation constant was 30±7 pM. Binding to mammary epithelium could be displaced by either the RIII or 34I-R strains of MMTV, and binding was blocked by antibodies to gp52. Levels in the liver and adrenal glands were only 25% of those in the mammary gland, while the concentrations in the ovary and salivary gland were intermediate. Scatchard analyses of the binding data suggested that there was only a single set of high-affinity binding sites. During late pregnancy and lactation, receptor levels in mammary epithelium rose threefold, while those in the liver and salivary gland were unchanged. This induction would result in the mammary gland having 12 times the gp52-binding protein than other tissues and may result in the preferential reinfection of this tissue during lactation, with subsequent tumour formation.