A new mouse model for the trisomy of the Abcg1-U2af1 region reveals the complexity of the combinatorial genetic code of down syndrome.
Mental retardation in Down syndrome (DS), the most frequent trisomy in humans, varies from moderate to severe. Several studies both in human and based on mouse models identified some regions of human chromosome 21 (Hsa21) as linked to cognitive deficits. However, other intervals such as the telomeric region of Hsa21 may contribute to the DS phenotype but their role has not yet been investigated in detail. Here we show that the trisomy of the 12 genes, found in the 0.59 Mb (Abcg1-U2af1) Hsa21 sub-telomeric region, in mice (Ts1Yah) produced defects in novel object recognition, open-field and Y-maze tests, similar to other DS models, but induces an improvement of the hippocampal-dependent spatial memory in the Morris water maze along with enhanced and longer lasting long-term potentiation in vivo in the hippocampus. Overall, we demonstrate the contribution of the Abcg1-U2af1 genetic region to cognitive defect in working and short-term recognition memory in DS models. Increase in copy number of the Abcg1-U2af1 interval leads to an unexpected gain of cognitive function in spatial learning. Expression analysis pinpoints several genes, such as Ndufv3, Wdr4, Pknox1 and Cbs, as candidates whose overexpression in the hippocampus might facilitate learning and memory in Ts1Yah mice. Our work unravels the complexity of combinatorial genetic code modulating different aspect of mental retardation in DS patients. It establishes definitely the contribution of the Abcg1-U2af1 orthologous region to the DS etiology and suggests new modulatory pathways for learning and memory.
Molecular Embryology and Immunology, Université d'Orléans, UMR6218, Orléans Cedex 2, France.
Patricia Lopes
PL
Pereira
Laetitia
L
Magnol
Ignasi
I
Sahún
Véronique
V
Brault
Arnaud
A
Duchon
Paola
P
Prandini
Agnès
A
Gruart
Jean-Charles
JC
Bizot
Bernadette
B
Chadefaux-Vekemans
Samuel
S
Deutsch
Fabrice
F
Trovero
José María
JM
Delgado-García
Stylianos E
SE
Antonarakis
Mara
M
Dierssen
Yann
Y
Herault
D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000818:Animals; D001007:Anxiety / Q000235:genetics; D004195:Disease Models, Animal; D004314:Down Syndrome / Q000235:genetics*; D054351:Electrical Synapses / Q000502:physiology; D005106:Exploratory Behavior; D017353:Gene Deletion; D018628:Gene Dosage; D020440:Gene Duplication; D005815:Genetic Code; D006801:Humans; D007858:Learning; D008074:Lipoproteins / Q000235:genetics*; D008568:Memory; D051379:Mice; D008817:Mice, Mutant Strains; D009043:Motor Activity / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics*; D012261:Ribonucleoproteins / Q000235:genetics*; D000072668:Splicing Factor U2AF; D014314:Trisomy / Q000235:genetics*
C487540:ABCG1 protein, mouse; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters; D008074:Lipoproteins; D009687:Nuclear Proteins; D012261:Ribonucleoproteins; D000072668:Splicing Factor U2AF; C000607494:U2AF2 protein, human; C000607495:Zrsr1 protein, mouse