title: A novel transmembrane transporter encoded by the XPCT gene in Xq13.2.
abstract: To study the regulation and chromosomal basis of X chromosome inactivation, we have physically characterized the region in Xq13.2 known to contain the X inactivation center (XIC), a locus required in cis for inactivation to occur. Here, we report a novel gene isolated by positional cloning in this region. The gene (previously identified as DXS128E) encodes a predicted 67 kDa protein containing twelve hydrophobic transmembrane domains, characteristic of a family of transporter proteins. Presence of an N-terminal PEST domain, consisting mainly of proline/glutamic acid repeats, suggests that the protein may be rapidly or conditionally degraded. We designate this gene XPCT for X-linked PEST-containing transporter. Expression studies suggest that XPCT is subject to X chromosome inactivation, being expressed only from the active X, despite mapping within 600 kb of the XIST gene which is expressed exclusively from the inactive X. Thus, a chromosomal switch in inactivation pattern occurs between these two genes on the X chromosome.
authors.affiliation: Department of Genetics, Case Western Reserve University School of Medicine, Cleveland, OH 44106.
authors.forename: R G
authors.initials: RG
authors.lastname: Lafrenière
authors.forename: L
authors.initials: L
authors.lastname: Carrel
authors.forename: H F
authors.initials: HF
authors.lastname: Willard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics*; D002874:Chromosome Mapping; D004303:Dosage Compensation, Genetic; D005260:Female; D005796:Genes; D006801:Humans; D006822:Hybrid Cells; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D027501:Monocarboxylic Acid Transporters; D016366:Open Reading Frames; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D027981:Symporters; D014960:X Chromosome
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D027501:Monocarboxylic Acid Transporters; C090735:SLC16A2 protein, human; D027981:Symporters