Gene identification in 1.6-Mb region of the Down syndrome region on chromosome 21

Miki Ohira*, Naohiko Seki, Takahiro Nagase, Emiko Suzuki, Nobuo Nomura, Osamu Ohara, Masahira Hattori, Yoshiyuki Sakaki, Toshihiko Eki, Yasufumi Murakami, Toshiyuki Saito, Hitoshi Ichikawa, Misao Ohki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

67 Citations (Scopus)


The Down syndrome [DS) region has been defined by analyses of partial trisomy 21. The 2.5-Mb region between D21S17 and ERG is reportedly responsible for the main features of DS. Within this 2.5-Mb region, we focused previously on a distal 1.6-Mb region from an analysis of Japanese DS patients with partial trisomy 21. Previously we also performed exon-trapping and direct cDNA library screening of a fetal brain cDNA library and identified a novel gene TPRD. Further screening of a fetal heart cDNA library was performed and a total of 44 possible exons and 97 cDNA clones were obtained and mapped on a BamHI map. By rescreening other cDNA libraries and a RACE. reaction, we isolated nearly full-length cDNAs of three additional genes [holocarboxylase synthetase (HCS), G protein-coupled inward rectifier potassium channel 2 (GIRK2), and a human homolog of Drosophila minibrain gene (MNB)] and a coding sequence of a novel inward rectifier potassium channel-like gene (IRKK). The gene distribution and direction of transcription were determined by mapping both ends of the cDNA sequences. We found that these genes, except IRKK, are expressed ubiquitously and are relatively large, extending from 100 kb to 300 kb on the genome. These nearly full-length cDNA sequences should facilitate understanding of the detailed genome structure of the DS region and help to elucidate their role in the etiology of DS.

Original languageEnglish
Pages (from-to)47-58
Number of pages12
JournalGenome Research
Issue number1
Publication statusPublished - 1997 Jan
Externally publishedYes

ASJC Scopus subject areas

  • Genetics


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