Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Recombinant dna technique included in method of making a...
Reexamination Certificate
2000-02-23
2002-04-09
Carlson, Karen Cochrane (Department: 1653)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Recombinant dna technique included in method of making a...
C435S320100, C435S252300, C435S325000, C536S023100, C536S023500, C530S350000
Reexamination Certificate
active
06368828
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to isoforms of the family of transcription factors known as Stat (signal transducers and activators of transcription). In particular, the present invention provides attenuated and dominant negative variants of human Stat6, which are designated Stat6b and Stat6c and which have differential effects on the modulation of Stat6 activity in cells.
2. Background Art
The Stats have been evolutionarily conserved from Drosophila to humans. Physiologically, Stat signaling pathways have been correlated with pleiotropic and mitogenic functional responses induced by a variety of growth factors, cytokines and interferons. In particular, Stat6 activation correlates with functional responses induced by interleukin-4 (IL-4) (22), interleukin-13 (IL-13) (25) and platelet-derived growth factor (PDGF) (26).
IL-4 is a pleiotropic cytokine that plays a prominent role in the regulation of inflammatory and cell-mediated immune responses (1). IL-4 treatment induces tyrosine phosphorylation of the IL-4 receptor, designated IL-4R&agr; (11, 12), a member of the hematopoietin receptor superfamily (13, 14). Unlike several members of the hematopoietin receptor superfamily, IL-4R&agr; is ubiquitously expressed on cells of hematopoietic and nonhematopoietic origin. IL-4R&agr; activation results in tyrosine phosphorylation of multiple substrates including Jak1, Jak3 (15, 16), IRS-1 (17), IRS-2/4PS (18) and Stat6 (13, 14, 19, 20). Phosphorylation of specific tyrosine residues within the two GYKXF motifs present in the IL-4R&agr; has been proposed to be crucial for binding to and activation of Stat6 (13, 22).
Selective activation of the Stats results in dimerization and translocation to the nucleus, where each interacts with unique DNA response elements and activates transcription (23, 24). Although phenotypic analysis of Stat6-/- mice have elegantly demonstrated a role for Stat6 in IL-4-induced lymphocyte proliferation, Th2 helper T cell differentiation, immunoglobulin class switching, and cell surface antigen expression (27-29), the mechanism(s) by which Stat6 induces these effects remain incompletely understood.
The present invention provides two previously unknown human Stat6 variants, Stat6b and Stat6c, that are a naturally occurring, attenuated variant and a naturally occurring dominant negative variant, respectively, of Stat6. Also provided is the entire genomic sequence of the human Stat6 gene, including chromosomal mapping and genetic linkage analysis.
SUMMARY OF THE INVENTION
The present invention provides an isolated nucleic acid encoding the polypeptide Stat6b, having an amino acid sequence of Stat6 wherein at least 110 amino acids are deleted at the amino terminus, as well as an isolated nucleic acid encoding the polypeptide Stat6b, having the nucleotide sequence of SEQ ID NO:1.
Further provided is an isolated polypeptide, Stat6b, having an amino acid sequence of Stat6 wherein at least 110 amino acids are deleted from the amino terminus, an isolated polypeptide, Stat6b, having an amino acid sequence of Stat6 wherein amino acids 39-86 are deleted at the amino terminus and an isolated polypeptide, Stat6b, having the amino acid sequence of SEQ ID NO:2.
In addition, the present invention provides an isolated nucleic acid encoding the polypeptide Stat6c, having an amino acid sequence of Stat6 wherein amino acids 537-564 are deleted and an isolated nucleic acid encoding the polypeptide Stat6c, having the nucleotide sequence of SEQ ID NO:3.
Also provided is an isolated polypeptide, Stat6c, having an amino acid sequence of Stat6 wherein amino acids 537-564 are deleted and an isolated polypeptide, Stat6c, having the amino acid sequence of SEQ ID NO:4.
A method of producing the polypeptide Stat6b or the polypeptide Stat6c is also provided, comprising culturing cells containing a vector comprising nucleic acid encoding Stat6b or nucleic acid encoding Stat6c under conditions whereby the polypeptide Stat6b or the polypeptide Stat6c is produced.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As used herein, “a” can include multiples.
The present invention provides the discovery of previously unknown isoforms of the human Stat6 gene, produced by differential splicing of the Stat6 gene, which have been identified as having distinct modulating functions within cells in which they are expressed. Specifically, a family of proteins termed signal transducers and activators of transcription (Stat) is known. Among the members of the Stat family is the protein Stat6 which has been isolated and cloned (See, ref 39 or U.S. Pat. No. 5,591,825 (McKnight, et al., issued Jan. 7, 1997)). Stat6 has been shown to play a role in interleukin-4 (IL-4) mediated signaling and may play a role in lymphoid cell proliferation and transcription. In studying the role of Stat6, two previously unknown, naturally occurring isoforms of Stat6 of the present invention, Stat6b and Stat6c, have been isolated and cloned. Any reference below to particular codons or base pairs of human Stat6 in describing the sequence of Stat6b or Stat6c are derived from the publicly available cDNA sequence of Stat6 as provided in SEQ ID NO:1 of U.S. Pat. No. 5,591,825 issued Jan. 7, 1997 or from the genomic sequence of human Stat6 provided herein as SEQ ID NO:5 and the cDNA sequence of wild type human Stat6 provided herein as SEQ ID NO:67.
The present invention provides an isolated nucleic acid encoding the polypeptide Stat6b, having an amino acid sequence of Stat6 wherein at least 110 amino acids are deleted at the amino terminus. For example, the nucleic acid can have a deletion encompassing the last base pair of codon 39 of Stat6 and continuing through to and including codon 86 of Stat6. Additionally, the nucleic acid of this invention can be an isolated nucleic acid encoding the polypeptide Stat6b, having the nucleotide sequence of SEQ ID NO:1.
In addition, the present invention provides an isolated nucleic acid encoding the polypeptide Stat6c, having an amino acid sequence of Stat6 wherein amino acids 537-564 are deleted. For example, the nucleic acid encoding the polypeptide Stat6c can have a deletion encompassing the last base pair of codon 536 of Stat6 and continuing through to and including the first two base pairs of codon 564 of Stat6. In addition, the present invention provides an isolated nucleic acid encoding the polypeptide Stat6c, having the nucleotide sequence of SEQ ID NO:3.
“Nucleic acid” as used herein refers to single- or double-stranded molecules which may be DNA, comprised of the nucleotide bases A, T, C and G, or RNA, comprised of the bases A, U (substitutes for T) , C, and G. The nucleic acid may represent a coding strand or its complement. Nucleic acids may be identical in sequence to the sequence which is naturally occurring or may include alternative codons which encode the same amino acid as that which is found in the naturally occurring sequence (39). Furthermore, nucleic acids may include codons which represent conservative substitutions of amino acids as described in Table I.
As used herein, the term “isolated” means a nucleic acid separated or substantially free from at least some of the other components of the naturally occurring organism, for example, the cell structural components commonly found associated with nucleic acids in a cellular environment and/or other nucleic acids. The isolation of nucleic acids can therefore be accomplished by techniques such as cell lysis followed by phenol plus chloroform extraction, followed by ethanol precipitation of the nucleic acids (30). The nucleic acids of this invention can be isolated from cells according to methods well known in the art for isolating nucleic acids. Alternatively, the nucleic acids of the present invention can be synthesized according to standard protocols well described in the literature for synthesizing nucleic acids.
The nucleic acid of this invention can be used as a probe or primer to identify the presence of a nucleic acid encoding the Stat6b or Stat6c polypeptide in a sample.
The nu
LaRochelle William
Patel Bharvin K. R.
Pierce Jacalyn H.
Carlson Karen Cochrane
Needle & Rosenberg P.C.
The United States of America as represented by the Department of
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