The methyl binding domain containing protein MBD5 is a transcriptional regulator responsible for 2q23.1 deletion syndrome

Abstract

2Iq23.1 microdeletion syndrome is a recently described rare disease that includes intellectual disability, motor delay, autistic-like behaviors, and craniofacial abnormalities. Dosage insufficiency of the methyl-CpG-binding domain protein 5 (MBD5) gene was suggested as the genetic cause, since all the described patients carry a partial or total heterozygous deletion of MBD5. We reported the generation and characterization of a mouse model with haploinsufficiency for Mbd5 that confirmed this hypothesis. As in human 2q23.1 microdeletion syndrome, the MBD5 (+/GT) mouse model exhibited abnormal social behavior, cognitive impairment, and motor and craniofacial abnormalities, supporting a causal role for MBD5 in 2q23.1 microdeletion syndrome. The use of mouse neuronal cultures uncovered a deficiency in neurite outgrowth, suggesting the participation of MBD5 in neuronal processes. The study of the MBD5 (+/GT) mouse advanced our understanding of the abnormal brain development associated with behavioral and cognitive symptoms.

Keywords: 2q23.1 microdeletion syndrome; Mbd5; autism; intellectual disabilities; mouse model; transcriptional regulator.

Figure 1.

Proliferating neural stem cells do not express MBD5. 2 month old Mbd5^+/GT mice were treated with BrdU 24 h before brain collection and processed for X-gal (left panel) and BrdU immunolabeling (center panel). BrdU positive cells (arrows, merged right panel and magnified inset) in the subgranular zone do not show X gal staining, suggesting that newly generated cells in the brain do not express MBD5. GCL: granule cell layer.