Christine Morris

Publications (2)10.14 Total impact

• Article: Localization of a gamma-glutamyl-transferase-related gene family on chromosome 22

  Christine Morris, Céline Courtay, Ad Geurts Kessel, Johanna Hoeve, Nora Heisterkamp, John Groffen
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  ABSTRACT: A gene family encompassing a minimum of four genes or pseudogenes for gamma-glutamyl transferase (GGT; EC 2.3.2.2) is present on chromosome 22q11. We have previously isolated a cDNA related to GGT but clearly not belonging to its gene family. The chromosomal location of this related gene, GGTLA1, has been determined by both isotopic and fluorescence in situ hybridization to metaphase cells and by Southern blot analysis of somatic cell hybrid DNAs. We show that GGTLA1 is part of a distinct gene family, which has at least four members (GGTLA1, GGTLA2, GGTLA3, GGTLA4). At least two loci are located on chromosome 22 within band q11 and proximal to the chronic myelogenous leukemia (CML) breakpoint in BCR (breakpoint cluster region gene). At least one other member is located more distally between the breakpoints found in Ewings sarcoma and CML. Some of the GGT and GGTLA family members are located on NotI restriction enzyme fragments of a similar size. Combined results indicate that a segment of human chromosome 22q11 has undergone largescale amplification events relatively recently in evolution.
  Human Genetics 02/1993; 91(1):31-36. · 5.07 Impact Factor
• Article: Chromosomal localization of the human glycoasparaginase gene to 4q32–q33

  Christine Morris, Nora Heisterkamp, John Groffen, Julian C. Williams, Ilkka Mononen
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  ABSTRACT: Glycoasparaginase cleaves the N-glycosidic linkage between asparagine and N-acetylglucosamine in the degradation of glycoproteins. In humans, a deficient activity of glycoasparaginase results in accumulation of glycoasparagines, causing the lysosomal storage disease aspartylglycosaminuria. Recombinant plasmid containing the cDNA insert encoding human glycoasparaginase was used to localize the enzyme to chromosome 4q32–q33 by in situ hybridization to metaphase chromosomes prepared from normal human lymphocytes.
  Human Genetics 12/1991; 88(3):295-297. · 5.07 Impact Factor