A novel long-range enhancer regulates postnatal expression of Zeb2: implications for Mowat-Wilson syndrome phenotypes

Abstract

The zinc-finger, E-box-binding homeobox-2 (Zeb2) gene encodes a SMAD-interacting transcription factor that has diverse roles in development and disease. Mutations at the hZeb2 locus cause Mowat-Wilson syndrome (MWS), a genetic disorder that is associated with mental retardation and other, case- and sex-dependent clinical features. Recent studies have detailed microRNA-mediated control of Zeb2, but little is known about the genomic context of this gene or of enhancer sequences that may direct its diverse functions. Here, we describe a novel transgenic rodent model in which Zeb2 regulatory sequence has been disrupted, resulting in a postnatal developmental phenotype that is autosomal dominant. The phenotype exhibits a genotype-by-sex interaction and manifests primarily as an acute attenuation of postnatal kidney development in males. Other aspects of embryonic and neonatal development, including neuronal, are unaffected. The transgene insertion site is associated with a 12 kb deletion, 1.2 Mb upstream of Zeb2, within a 4.1 Mb gene desert. A conserved sequence, derived from the deleted region, enhanced Zeb2 promoter activity in transcription assays. Tissue and temporal restriction of this enhancer activity may involve postnatal changes in proteins that bind this sequence. A control human/mouse VISTA enhancer (62 kb upstream of Zeb2) also up-regulated the Zeb2 promoter, providing evidence of a string of conserved distal enhancers. The phenotype arising from deletion of one copy of the extreme long-range enhancer indicates a critical role for this enhancer at one developmental stage. Haploinsufficiency of Zeb2 in this developmental context reflects inheritance of MWS and may underlie some sex-dependent, non-neural characteristics of this human inherited disorder.

Pleiotropic Associations of Allelic Variants in a 2q22 Region with Risks of Major Human Diseases and Mortality

“…Function of ZEB2 can be directed in a tissue- and age-dependent manner by long- (1.2 Mb) and short- (62 Kb) distance enhancers suggesting a conserved regulatory string of enhancers for ZEB2 and possibly ACVR2A [43]. Other long-range enhancers for ZEB2 were also observed [44,45].…”

Absence of a simple code: how transcription factors read the genome

“…In metazoans, by contrast, regulatory sequences often fall tens of kilobases or even megabases from the TSS of the target gene [118–120]. These distal elements can be upstream or downstream of the target gene, and they regularly bypass intervening genes (Figure 5C).…”

Zeb2: A multifunctional regulator of nervous system development

“…being crucial for a tissue-and sex-specific role of Zeb2 at one developmental stage using a transgenic rodent model (El-Kasti et al, 2012). The temporal and spatial regulation of Zeb2 enhancer regions likely contributes to the multifarious roles of Zeb2, and their deregulation may lead to pathogenic processes.…”