Isolation of a new gene from the distal short arm of the human X chromosome that escapes X-inactivation.
A gene, designated GS1, was identified by its association with a CpG island approximately 100 kb telomeric to the steroid sulfatase (STS) locus on the distal short arm of the human X chromosome. Both cDNA and genomic clones of the GS1 gene have been isolated and characterized. The cDNA clone detects a 2.3 kb transcript in human placenta and fibroblasts, and may encode a protein of 214 amino acid residues. Although sequences homologous to GS1 cDNA are present on chromosomes 1, 20, X, and Y, the functional GS1 gene is on the X chromosome. The GS1 gene appears to be non-essential, as there are no obvious clinical differences between STS deficient patients with point mutations in the STS gene, and patients with a deletion of the STS and GS1 genes. The GS1 gene is expressed from mouse-human cell hybrids containing active or inactive human X chromosomes, indicating that it escapes X inactivation. Characterization of GS1 genomic clones revealed that the gene consists of 4 exons spanning over 105 kb, with its transcriptional direction opposite to that of the STS gene. The isolation and characterization of a new gene which escapes X inactivation from distal Xp is of interest as it adds to our understanding of the structural organization of the human X chromosome and may help in providing clues regarding the mechanism of X-inactivation.
Yen
P H
PH
Howard Hughes Medical Institute, Torrance, CA.
Ellison
J
J
Salido
E C
EC
Mohandas
T
T
Shapiro
L
L
D000595:Amino Acid Sequence; D001192:Arylsulfatases / Q000235:genetics; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal; D002878:Chromosomes, Human, Pair 1; D002890:Chromosomes, Human, Pair 20; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D015226:Dinucleoside Phosphates / Q000032:analysis; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D043266:Steryl-Sulfatase; D016615:Telomere; D014960:X Chromosome; D014998:Y Chromosome
D001192:Arylsulfatases; D004247:DNA; D015226:Dinucleoside Phosphates; D012313:RNA; D043266:Steryl-Sulfatase; C015772:CpG dinucleotide