title: Human chromosome 21q22.2-qter carries a gene(s) responsible for downregulation of mlc2a and PEBP in Down syndrome model mice.
abstract: Congenital heart disease (CHD) is a major clinical manifestation of Down syndrome (DS). We recently showed that chimeric mice containing a human chromosome 21 (Chr 21) exhibited phenotypic traits of DS, including CHD. Our previous study showed that myosin light chain-2a (mlc2a) expression was reduced in the hearts of chimeric mice and DS patients. We found that phosphatidylethanolamine binding protein (PEBP) was also downregulated in Chr 21 chimeras in this study. As mlc2a is involved in heart morphogenesis, and PEBP controls the proliferation and differentiation of different cell types, these genes are candidates for involvement in DS-CHD. The DS-CHD candidate region has been suggested to span between PFKL and D21S3, which is the STS marker near the ETS2 loci. To identify gene(s) or a gene cluster on Chr 21 responsible for the downregulation of mlc2a and PEBP, we fragmented Chr 21 at the EST2 loci, by telomere-directed chromosome truncation in homologous recombination-proficient chicken DT40 cells. The modified Chr 21 was transferred to mouse ES cells by microcell-mediated chromosome transfer (MMCT), via CHO cells. We used ES cell lines retaining the Chr 21 truncated at the ETS2 locus (Chr 21E) to produce chimeric mice and compared overall protein expression patterns in hearts of the chimeras containing the intact and the fragmented Chr 21 by two-dimensional electrophoresis. While mouse mlc2a and PEBP expression was downregulated in the chimeras containing the intact Chr 21, the expression was not affected in the Chr 21E chimeras. Therefore, we suggest that Chr 21 gene(s) distal from the ETS2 locus reduce mouse mlc2a and PEBP expression in DS model mice and DS. Thus, this chromosome engineering technology is a useful tool for identification or mapping of genes that contribute to the DS phenotypes.
authors.affiliation: Department of Molecular and Cell Genetics, Graduate School of Medical Science, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kazuki
authors.forename: Motoshi
authors.initials: M
authors.lastname: Kimura
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Nishigaki
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Kai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Abe
authors.forename: Chiga
authors.initials: C
authors.lastname: Okita
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Shirayoshi
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Schulz
authors.forename: Kazuma
authors.initials: K
authors.lastname: Tomizuka
authors.forename: Kazunori
authors.initials: K
authors.lastname: Hanaoka
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Inoue
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Oshimura
mesh_terms: D000727:Androgen-Binding Protein; D000818:Animals; D024722:Cardiac Myosins / Q000235:genetics* / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D004195:Disease Models, Animal; D004314:Down Syndrome / Q000235:genetics* / Q000378:metabolism*; D015536:Down-Regulation / Q000235:genetics; D005786:Gene Expression Regulation; D006330:Heart Defects, Congenital / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009206:Myocardium / Q000378:metabolism; D018994:Myosin Light Chains / Q000235:genetics* / Q000378:metabolism*; D049488:Phosphatidylethanolamine Binding Protein; D049294:Phospholipid Transfer Proteins
chemical_list: D000727:Androgen-Binding Protein; D002352:Carrier Proteins; D018994:Myosin Light Chains; C511482:PEBP1 protein, human; D049488:Phosphatidylethanolamine Binding Protein; D049294:Phospholipid Transfer Proteins; C107184:myosin light chain 2; D024722:Cardiac Myosins