The present invention relates to the discovery, identification, and characterization of novel human polynucleotides encoding proteins that share sequence similarity with mammalian transporter proteins. The invention encompasses the described polynucleotides, host cell expression systems, the encoded proteins, fusion proteins, polypeptides and peptides, antibodies to the encoded proteins and peptides, and genetically engineered animals that either lack or over express the disclosed polynucleotides, antagonists and agonists of the proteins, and other compounds that modulate the expression or activity of the proteins encoded by the disclosed polynucleotides that can be used for diagnosis, drug screening, clinical trial monitoring, and treatment of diseases and disorders.
Transporter proteins are integral membrane proteins that mediate or facilitate the passage of materials across the lipid bilayer. Given that the transport of materials across the membrane can play an important physiological role, transporter proteins are good drug targets. Additionally, one of the mechanisms of drug resistance involves diseased cells using cellular transporter systems to export chemotherapeutic agents from the cell. Such mechanisms are particularly relevant to cells manifesting resistance to a multiplicity of drugs.
The present invention relates to the discovery, identification, and characterization of nucleotides that encode novel human proteins, and the corresponding amino acid sequences of these proteins. The novel human proteins (NHPS) described for the first time herein share structural similarity with mammalian ion transporters, calcium transporters (particularly calcium transporting ATPases), sulfate transporters, and zinc transporters.
The novel human nucleic acid sequences described herein, encode alternative proteins/open reading frames (ORFS) of 1,177 and 374 amino acids in length (calcium-transporting ATPase, SEQ ID NOS: 2 and 4), 970 (sulfate transporter, SEQ ID NO:7), and 507 (zinc transporter, SEQ ID NO:10) amino acids in length.
The invention also encompasses agonists and antagonists of the described NHPs, including small molecules, large molecules, mutant NHPs, or portions thereof, that compete with native NHP, peptides, and antibodies, as well as nucleotide sequences that can be used to inhibit the expression of the described NHPs (e.g., antisense and ribozyme molecules, and gene or regulatory sequence replacement constructs) or to enhance the expression of the described NHP polynucleotides (e.g., expression constructs that place the described polynucleotide under the control of a strong promoter system), and transgenic animals that express a NHP transgene, or xe2x80x9cknock-outsxe2x80x9d (which can be conditional) that do not express a functional NHP. Knock-out mice can be produced in several ways, one of which involves the use of mouse embryonic stem cells (xe2x80x9cES cellsxe2x80x9d) lines that contain gene trap mutations in a murine homolog of at least one of the described NHPs. When the unique NHP sequences described in SEQ ID NOS:1-11 are xe2x80x9cknocked-outxe2x80x9d they provide a method of identifying phenotypic expression of the particular gene as well as a method of assigning function to previously unknown genes. Additionally, the unique NHP sequences described in SEQ ID NOS:1-11 are useful for the identification of coding sequence and the mapping a unique gene to a particular chromosome.
Further, the present invention also relates to processes for identifying compounds that modulate, i.e., act as agonists or antagonists, of NHP expression and/or NHP activity that utilize purified preparations of the described NHPs and/or NHP product, or cells expressing the same. Such compounds can be used as therapeutic agents for the treatment of any of a wide variety of symptoms associated with biological disorders or imbalances.
The Sequence Listing provides the sequences of the described NHP ORFs that encode the described NHP amino acid sequences. SEQ ID NOS 5, 8, and 11 describe nucleotides encoding NHP ORFs along with regions of flanking sequence.