Juxtacentromeric region of human chromosome 21: a boundary between centromeric heterochromatin and euchromatic chromosome arms.
We have analysed the genomic structure and transcriptional activity of a 2.3-Mb genomic sequence in the juxtacentromeric region of human chromosome 21. Our work shows that this region comprises two different chromosome domains. The 1.5-Mb proximal domain: (i) is a patchwork of chromosome duplications; (ii) shares sequence similarity with several chromosomes; (iii) contains several gene fragments (truncated genes having an intron/exon structure) intermingled with retrotransposed pseudogenes; and (iv) harbours two genes (TPTE and BAGE2) that belong to gene families and have a cancer and/or testis expression profile. The TPTE gene family was generated before the branching of Old World monkeys from the great ape lineage, by intra- and interchromosome duplications of the ancestral TPTE gene mapping to phylogenetic chromosome XIII. By contrast, the 0.8-Mb distal domain: (i) is devoid of chromosome duplications; (ii) has a chromosome 21-specific sequence; (iii) contains no gene fragments and only one retrotransposed pseudogene; and (iv) harbours six genes including housekeeping genes. G-rich sequences commonly associated with duplication termini cluster at the boundary between the two chromosome domains. These structural and transcriptional features lead us to suggest that the proximal domain has heterochromatic properties, whereas the distal domain has euchromatic properties.
Brun
Marie-Elisabeth
ME
Institut de Génétique Humaine, CNRS UPR 1142, 141, rue de la Cardonille, 34396 Montpellier, France.
Ruault
Myriam
M
Ventura
Mario
M
Roizès
Gérard
G
De Sario
Albertina
A
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics; D017398:Alternative Splicing; D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics; D001482:Base Composition; D015152:Blotting, Northern; D002460:Cell Line; D002503:Centromere / Q000235:genetics*; D002874:Chromosome Mapping; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D030561:Databases, Nucleic Acid; D022041:Euchromatin / Q000235:genetics; D005260:Female; D020440:Gene Duplication; D015870:Gene Expression; D006570:Heterochromatin / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases / Q000235:genetics; D011544:Pseudogenes / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D018626:Retroelements / Q000235:genetics; D017422:Sequence Analysis, DNA
C470491:ABCC13 pseudogene, human; D018528:ATP-Binding Cassette Transporters; D033942:Adaptor Proteins, Vesicular Transport; D000951:Antigens, Neoplasm; C092706:BAGE protein, human; C490498:BAGE2 protein, human; D018076:DNA, Complementary; D022041:Euchromatin; D006570:Heterochromatin; D008565:Membrane Proteins; C477825:RBM11 protein, human; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D018626:Retroelements; C435526:SAMSN1 protein, human; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases; C446603:TPTE protein, human; D051059:PTEN Phosphohydrolase