title: Homologous genomic fragments in the mouse pre-T cell receptor alpha (pTa) and Xist loci.
abstract: We recently characterized a genomic region located upstream of the mouse pre-T cell receptor alpha (pTa) gene, which controls pTa expression in pre-T cells. We now report an unexpected homology between this region and a region in the mouse X chromosome inactivation center between the 3' end of the Xist gene and the start of an antisense transcript Tsix. The homology is extended over 4 kb of genomic sequence split by an expanded repeat region and is observed only in the mouse, not in the rat. Despite high sequence similarity to the pTa transcriptional enhancer, the homologous X chromosome fragment appears to have lost its enhancer activity. These data underscore the complex organization of the mouse genome and, in particular, of the X chromosome inactivation center.
authors.affiliation: Department of Genetics and Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: B
authors.initials: B
authors.lastname: Reizis
authors.forename: J T
authors.initials: JT
authors.lastname: Lee
authors.forename: P
authors.initials: P
authors.lastname: Leder
mesh_terms: D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002460:Cell Line; D004303:Dosage Compensation, Genetic; D004742:Enhancer Elements, Genetic; D005260:Female; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D051381:Rats; D016693:Receptors, Antigen, T-Cell, alpha-beta; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics*; D014960:X Chromosome / Q000235:genetics*
chemical_list: D008562:Membrane Glycoproteins; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D016693:Receptors, Antigen, T-Cell, alpha-beta; D014157:Transcription Factors; C077885:XIST non-coding RNA; C090377:pre-T cell receptor alpha