Egf receptor mrna and protein in rat exorbital lacrimal acinar
cells. evidence of its egf dependent phosphotyrosilation.
Marechal, Herv[acute]e, Helene Jammes, Bernard Rossignol, and Philippe
Mauduit.
Laboratoire de Biochimie des Transports Cellulaires, CNRS, URA
1116, Bat. 432, Universit[acute]e Paris-Sud, 91405 Orsay Cedex,
France
APStracts 2:0380C, 1995.
This study was designed to demonstrate the presence of the EGF
receptor in the rat exorbital lacrimal gland. EGF receptor gene
transcription was demonstrated 1/ by RT-PCR analysis of lacrimal
gland and acinar cells RNA using a set of specific primers deduced
from the rat EGF receptor sequence and 2/ by Northern blot analysis
of rat lacrimal gland mRNA. Lacrimal acinar cells preparations
contain a low but detectable amount of specific 125I-EGF binding
sites and efficiently internalized the ligand upon binding at 37 C. A
sheep polyclonal antibody, directed against the human EGF receptor,
detect a protein of 170 kDa by Western blot analysis of membrane
proteins of the whole gland. This protein can be immunoprecipitated
by the same antibody from whole gland membrane proteins as well as
from solubilized acinar cells. Incubations of acinar cells in the
presence of EGF results in an increased content of tyrosine
phosphorylated residues in immunoprecipitated p170. Taken together,
these results demonstrate for the first time both EGF receptor gene
transcription and EGFR protein expression in a lacrimal tissue, i-e,
the rat exorbital lacrimal gland. These results also suggest a
specific cellular location of the EGFR in a cell population contained
in acinar cells preparations.
Received 22 August 1995; accepted in final form 16 October 1995.
APS Manuscript Number C520-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95