Address for correspondence: Nita J. Maihle, Ph. D., 200 First Street SW, Rochester, MN 55905. Voice: 507-284-0279; fax: 507-284-1767.
maihle{at}mayo.edu
Ann. N.Y. Acad. Sci. 995: 39-47 (2003).
The epidermal growth factor receptor (EGFR) and related family
members (ERBB2, ERBB3, and ERBB4) previously have been shown
to play pivotal roles in the development of female reproductive
tissues, in blastocyst implantation, and in placental differentiation.
We have cloned and sequenced several naturally occurring alternative
transcripts of the human and mouse
EGFR genes, which encode
novel receptor isoforms containing varying portions of the extracellular
ligand-binding domain, but lacking the transmembrane and cytoplasmic
domain sequences. The human 1.8-kb and 3-kb alternative
EGFR transcripts encode secreted 60-kDa and cell surface-associated
110-kDa EGFR isoforms, respectively. We have developed quantitative
ribonuclease protection assays to study the expression of these
alternative transcripts in human tissues. Similar to the full-length
EGFR mRNAs, the highest expression level of these alternative
transcripts occurs in placenta. We speculate that both of these
EGFR isoforms may be important regulators of EGF-mediated cell
growth and differentiation in human placenta.
