title: drp, a novel protein expressed at high cell density but not during growth arrest.
abstract: Contact is a vital mechanism used by cells to interact with their environment. Contact with living and nonliving elements adjacent to a cell is the basis for many common biological events ranging from growth regulation to metastasis to embryonic pattern formation. We describe the cloning and characterization of a novel density-regulated protein (drp) whose expression is increased in cultured cells at high density compared with cells at low density. A drp cDNA was isolated from the human teratocarcinoma cell line PA-1. Northern analysis with a drp probe revealed transcripts of 2.8 and 3.2 kb. The drp RNA was expressed in a variety of tissues, with the highest amounts in skeletal and cardiac muscle. Using antipeptide antisera, increasing amounts of a 70-kDa protein were detected using several experimental approaches in several cells lines as cell density is increased. Conditioned medium from high-density cells was unable to induce expression of drp in cells growing at low density. Similarly, growth arrest by serum starvation or transforming growth factor-beta (TGF-beta) treatment failed to elicit drp expression. We conclude that drp is a novel protein whose expression is increased at high cell density but not growth arrest.
authors.affiliation: Department of Tumor Biology, The University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Deyo
authors.forename: P J
authors.initials: PJ
authors.lastname: Chiao
authors.forename: M A
authors.initials: MA
authors.lastname: Tainsky
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002452:Cell Count; D018797:Cell Cycle Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D003001:Cloning, Molecular; D017077:Culture Media, Conditioned / Q000494:pharmacology; D039642:Eukaryotic Initiation Factors; D016193:G1 Phase / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D018243:Teratocarcinoma; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D018797:Cell Cycle Proteins; D017077:Culture Media, Conditioned; C112641:DENR protein, human; D039642:Eukaryotic Initiation Factors; D009363:Neoplasm Proteins; D016212:Transforming Growth Factor beta