Identification of a novel candidate gene in the iron-sulfur pathway implicated in ataxia-susceptibility: human gene encoding HscB, a J-type co-chaperone.
Iron-sulfur proteins participate in a wide range of biochemical processes, including many that are central to mitochondrial electron transfer and energy metabolism. Mutations in two such proteins, frataxin and ABCB7, cause Friedreich ataxia and X-linked sideroblastic anemia with ataxia, respectively, rendering other participants in this pathway functional candidates for hereditary ataxia syndromes. Recently frataxin was shown to have an identical phylogenetic distribution with two genes and was most likely specifically involved in the same sub-process in iron-sulfur cluster assembly as one gene, designated hscB, in bacteria. To set the stage for an analysis of the potential role of this candidate gene in human disease, we defined the human HscB cDNA, its genomic locus, and its pattern of expression in normal human tissues. The isolated human HscB cDNA spans 785 bp and encodes a conserved 235-amino-acid protein, including a putative mitochondrial import leader. The HscB gene is found at chromosome 22q11-12 and is composed of six exons and five introns. Northern blot analyses of RNA from adult and fetal tissues defined a pattern of expression in mitochondria-rich tissues similar to that of frataxin, an expression pattern compatible with its implied role in mitochondrial energetics and related disease phenotypes.
Sun
Guifeng
G
Department of Physiology and Biophysics, University of California, Sprague Hall, Rm 328, 839 Medical Sciences Court, Irvine, CA 92697-4034, USA.
Gargus
J Jay
JJ
Department of Physiology and Biophysics, University of California, Sprague Hall, Rm 328, 839 Medical Sciences Court, Irvine, CA 92697-4034, USA. jjgargus@uci.edu.|Division of Human Genetics, Department of Pediatrics, University of California, Irvine, CA, USA. jjgargus@uci.edu.
Ta
Dennis T
DT
Department of Physiology and Biophysics, University of California, Sprague Hall, Rm 328, 839 Medical Sciences Court, Irvine, CA 92697-4034, USA.
Vickery
Larry E
LE
Department of Physiology and Biophysics, University of California, Sprague Hall, Rm 328, 839 Medical Sciences Court, Irvine, CA 92697-4034, USA.
D000595:Amino Acid Sequence; D001259:Ataxia / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D030541:Databases, Genetic; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D020022:Genetic Predisposition to Disease; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013455:Sulfur / Q000378:metabolism*
D029968:Escherichia coli Proteins; C490651:HSCB protein, human; D006360:Heat-Shock Proteins; C095453:HscB protein, E coli; D018832:Molecular Chaperones; D013455:Sulfur; D007501:Iron