Cux2(Cutl2) integrates neural progenitor development with cell-cycle progression during spinal cord neurogenesis

Abstract

Neurogenesis requires the coordination of neural progenitor proliferation and differentiation with cell-cycle regulation. However, the mechanisms coordinating these distinct cellular activities are poorly understood. Here we demonstrate for the first time that a Cut-like homeodomain transcription factor family member, Cux2 (Cutl2), regulates cell-cycle progression and development of neural progenitors. Cux2 loss-of-function mouse mutants exhibit smaller spinal cords with deficits in neural progenitor development as well as in neuroblast and interneuron differentiation. These defects correlate with reduced cell-cycle progression of neural progenitors coupled with diminished Neurod and p27Kip1 activity. Conversely, in Cux2 gain-of-function transgenic mice, the spinal cord is enlarged in association with enhanced neuroblast formation and neuronal differentiation, particularly with respect to interneurons. Furthermore, Cux2 overexpression induces high levels of Neurod and p27 Kip1. Mechanistically, we discovered through chromatin immunoprecipitation assays that Cux2 binds both the Neurod and p27Kip1 promoters in vivo, indicating that these interactions are direct. Our results therefore show that Cux2 functions at multiple levels during spinal cord neurogenesis. Cux2 initially influences cell-cycle progression in neural progenitors but subsequently makes additional inputs through Neurod and p27 Kip1 to regulate neuroblast formation, cell-cycle exit and cell-fate determination. Thus our work defines novel roles for Cux2 as a transcription factor that integrates cell-cycle progression with neural progenitor development during spinal cord neurogenesis.

1000 Genomes-based imputation identifies novel and refined associations for the Wellcome Trust Case Control Consortium phase 1 Data

“…These two SNPs are 780 kb apart, however, the CUX2 gene has been shown to directly regulate the expression of NeuroD, a gene that can cause T1D when mutated. 21 The lead SNPs for these two refined loci (IL23R for CD and CUX2 for T1D) are no longer genome-wide significant after conditioning on the nearest lead SNPs reported in literature to date. 18,22 Figure 1 Regional plots for two novel (missed) and two refined loci.…”

Cux2functions downstream of Notch signaling to regulate dorsal interneuron formation in the spinal cord

“…Previously, we determined that Cux2 (cut-like homeobox 2) regulates cell cycle progression and cell fate acquisition during ventral spinal cord neurogenesis (Iulianella et al, 2008). Here we characterize a role for Cux2 as a putative Notch effector gene that regulates dorsal interneuron development.…”

“…The generation, genotyping and phenotyping of Cux2, Rbpjκ, flox-stop Notch1 intracellular domain (NICD)-ires-EGFP, Wnt1-Cre and Nestin-Cre lines of mice were performed as previously described (Iulianella et al, 2008;Oka et al, 1995;Murtaugh et al, 2003;Chai et al, 2000;Dubois et al, 2006).…”

“…Embryos were then rinsed in PBS, fixed and processed for cryosectioning. Cux2 immunohistochemistry was performed using Cux2 antibodies (Iulianella et al, 2008). Mouse embryos were cultured in a whole-embryo roller culture incubator (BTC Engineering) in 100% rat serum supplemented with 2 mg/ml glucose and penicillin-streptomycin (R-100 Medium) maintained in a 60% O 2 /5% CO 2 /35% N 2 atmosphere at 37°C.…”

Bmp signaling regulates a dose-dependent transcriptional program to control facial skeletal development

“…The closely related gene Cux1 is regulated by Tgf and represses collagen expression (Fragiadaki et al, 2011). Cux2 is regulated by Notch signaling in the spinal cord, where it controls the balance between neural progenitors and differentiated neurons by modulating cell cycle progression and enhancing interneuron fate (Iulianella et al, 2008;Iulianella et al, 2009). Interestingly, Notch has been shown to work in parallel with Bmp signaling in valve development, suggesting that Notch and Bmp signaling may work together to regulate the balance of CNC progenitors with differentiated skeletal cells (Luna-Zurita et al, 2010).…”