Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
1998-10-13
2003-10-28
Zitomer, Stephanie W. (Department: 1634)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C536S024300, C536S023500, C536S024330, C536S024310, C530S350000, C435S006120, C435S325000, C435S252300, C435S320100
Reexamination Certificate
active
06639060
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to genes which encode novel proteins related to a family of receptor proteins typified by two related membrane spanning tyrosine kinases: the Epidermal Growth Factor receptor (EGFR), which is encoded by the erbB gene, the normal human counterpart of an oncogene (v-erbB) that was first recognized in the proviral DNA of avian erythroblastosis virus; and the receptor encoded by the related gene erbB-2. In particular, the present invention relates to a DNA segment encoding the coding sequence, or a unique portion thereof, for a third member of this receptor gene family, herein designated erbB-3.
BACKGROUND OF THE INVENTION
Proto-oncogenes encoding growth factor receptors constitute several distinct families with close overall structural homology. The highest degree of homology is observed in their catalytic domains, essential for the intrinsic tyrosine kinase activity of these proteins. Examples of such receptor families include: the EGFR and the related product of the erbB-2 oncogene; the Colony Stimulating Factor 1 receptor (CSF-1-R) and the related Platelet-Derived Growth Factor receptor (PDGF-R); the insulin receptor (IR) and the related Insulin-like Growth factor 1 receptor (IGF-1R); and the receptors encoded by the related oncogenes eph and elk.
It is well established that growth factor receptors in several of these families play critical roles in regulation of normal growth and development. Recent studies in Drosophila have emphasized how critical and multifunctional are developmental processes mediated by ligand-receptor interactions. An increasing number of Drosophila mutants with often varying phenotypes have now been identified as being due to lesions in genes encoding such proteins. The genetic locus of the Drosophila EGFR homologue, designated DER, has recently been identified as being alilelic to the zygotic embryonic lethal faint little ball exhibiting a complex phenotype with deterioration of multiple tissue components of ectodermal origin. Furthermore, other mutants appear to lack DER function either in the egg or the surrounding maternal tissue. Thus, the DER receptor may play an important role in the ligand-receptor interaction between egg and follicle cells necessary for determination of correct shape of eggshell and embryo. It is not yet known whether DER represents the sole Drosophila counterpart of known mammalian erbB-related genes.
Some of these receptor molecules have been implicated in the neoplastic process as well. In particular, both the erbB and erbB-2 genes have been shown to be activated as oncogenes by mechanisms involving overexpression or mutations that constitutively activate the catalytic activity of their encoded receptor proteins (Bargmann, C. I., Hung, M. C. & Weinberg, R. A., 1986,
Cell
45:649-657; Di Fiore, P. P., Pierce, J. H., Kraus, M. H., Segatto, O., King, C. R. & Aaronson, S. A., 1987,
Science
237:178-182; Di Fiore, P. P., Pierce, J. H., Fleming, T. P., Hazan, R., Ullrich, A., King, C. R., Schlessinger, J. & Aaronson, S. A., 1987,
Cell
51:1063-1070; Velu, T. J., Beguinot, L., Vass, W. C., Willingham, M. C., Merlino, G. T., Pastan, I. & Lowy, D. R., 1987,
Science
238:1408-1410). Both erbB and erbB-2 have been causally implicated in human malignancy. erbB gene amplification or overexpression, or a combination of both, has been demonstrated in squamous cell carcinomas and glioblastomas (Libermann, T. A., Nusbaum, H. R., Razon, N., Kris, R., Lax, I., Soreq, H., Whittle, N., Waterfield, M. D., Ullrich, A. & Schlessinger, J., 1985,
Nature
313:144-147). erbB-2 amplification and overexpression have been observed in human breast and ovarian carcinomas (King, C. R., Kraus, M. H. & Aaronson, S. A, 1985,
Science
229:974-976; Slamon, D. J., Godolphin, W., Jones, L. A., Holt, J. A., Wong, S. G., Keith, D. E., Levin, W. J., Stuart, S. G., Udove, J., Ullrich, A. & Press, M. F., 1989,
Science
244:707-712), and erbB-2 overexpression has been reported to be an important prognostic indicator of particularly aggressive tumors (Slamon, D. J., et al., 1989, supra). Yet, not all such tumors have been found to overexpress erbB-2, and many human tumors have not yet been associated with any known oncogene. Thus, there has been a continuing need to search for additional oncogenes which would provide knowledge and methods for diagnosis and, ultimately, for rational molecular therapy of human cancers.
Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.
SUMMARY OF THE INVENTION
It is an object of present invention to provide a DNA segment encoding a receptor protein related to the erbB proto-oncogene family which previously has not been known or even suspected to exist. Further, it is an object of the present invention to develop assays for expression of the RNA and protein products of such genes to enable determining whether abnormal expression of such genes is involved in human cancers. Thus, further objects of this invention include providing antibodies, either polyclonal or monoclonal, specific to a unique portion of the receptor protein; a method for detecting the presence of an erbB-3 ligand that is capable of either activating or down-regulating the receptor protein as well as procedures for purifying the resultant ligand; a method of screening potential ligand analogs for their ability to activate the receptor protein; and procedures for targeting a therapeutic drug to cells having a high level of the receptor protein.
In pursuit of the above objects, the present inventors have discovered a human genomic DNA fragment that is produced by cleavage with the SacI restriction enzyme, has a size of about 9 kbp, and is detectable by nucleic acid hybridization with a probe derived from the v-erbB gene only under reduced stringency hybridization conditions. Thus, this DNA fragment is distinct from those known to encode the epidermal growth factor receptor (EGFR) (i.e., the erbB gene) and from the related erbB-2 gene. Characterization of this DNA fragment after partial purification and molecular cloning showed that the region of v-erbB homology mapped to three exons that encode amino acid sequences having homologies of 64% and 67% to contiguous regions within the tyrosine kinase domains of the EGFR and erbB-2 proteins, respectively. A probe derived from the genomic DNA clone identified cDNA clones of the related mRNA which encode a predicted 148 kd transmembrane polypeptide with structural features identifying it as a member of the erbB family, prompting designation of the new gene as erbB-3. This gene was mapped to human chromosome 12q11-13 and was shown to be expressed as a 6.2 kb transcript in a variety of normal tissues of epithelial origin. Markedly elevated erbB-3 mRNA levels were demonstrated in certain human mammary tumor cell lines.
The predicted human erbB-3 gene product is closely related to EGFR and erbB-2, which have been implicated as oncogenes in model systems and human neoplasia. The erbB-3 coding sequence was expressed in NIH/3T3 fibroblasts and its product was identified as a 180 kDa glycoprotein, gp180
erbB-3
. Tunicamycin and pulse-chase experiments revealed that the mature protein was processed by N-linked glycosylation of a 145 kDa erbB-3 core polypeptide. The intrinsic catalytic function of gp180
erbB-3
was uncovered by its ability to autophosphorylate in vitro. Ligand-dependent signaling of its cytoplasmic domain was established employing transfectants which express a chimeric EGFR/erbB-3 protein, gp180
EGFR/erbB-3
. EGF induced tyrosine phosphorylation of the chimera and promoted soft agar colony formation of such transfectants. These findings, combined with the detection of constitutive tyrosine phosphorylation of gp180
erbB-3
in 4 out of 12 human mammary tumor cell lines, implicates the activated erbB-3 product in the pathogenesis of some human malignancie
Aaronson Stuart A.
Kraus Matthias H.
Forman BJ
Needle & Rosenberg P.C.
The United States of America as represented by the Department of
Zitomer Stephanie W.
LandOfFree
erbB-3 nucleic acids does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with erbB-3 nucleic acids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and erbB-3 nucleic acids will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3170844