The CHARGE syndrome-associated protein FAM172A controls AGO2 nuclear import.

CHARGE syndrome is a neural crest-related disorder mainly caused by mutation of the chromatin remodeler-coding gene Alternative causes include mutation of other chromatin and/or splicing factors. One of these additional players is the poorly characterized FAM172A, which we previously found in a complex with CHD7 and the small RNA-binding protein AGO2 at the chromatin-spliceosome interface. Focusing on the FAM172A-AGO2 interplay, we now report that FAM172A is a direct binding partner of AGO2 and, as such, one of the long sought-after regulators of AGO2 nuclear import.

NR2F1 regulates a Schwann cell precursor-vs-melanocyte cell fate switch in a mouse model of Waardenburg syndrome type IV.

Waardenburg syndrome type 4 (WS4) combines abnormal development of neural crest cell (NCC)-derived melanocytes (causing depigmentation and inner ear dysfunction) and enteric nervous system (causing aganglionic megacolon). The full spectrum of WS4 phenotype is present in Spot mice, in which an insertional mutation close to a silencer element leads to NCC-specific upregulation of the transcription factor-coding gene Nr2f1. These mice were previously found to develop aganglionic megacolon because of NR2F1-induced premature differentiation of enteric neural progenitors into enteric glia.

CHARGE syndrome-associated proteins FAM172A and CHD7 influence male sex determination and differentiation through transcriptional and alternative splicing mechanisms.

To gain further insight into chromatin-mediated regulation of mammalian sex determination, we analyzed the role of the CHARGE syndrome-associated proteins FAM172A and CHD7. This study is based on our prior discoveries that a subset of corresponding mutant mice display complete male-to-female sex reversal, and that both of these proteins regulate co-transcriptional alternative splicing in neural crest cells. Here, we report that FAM172A and CHD7 are present in the developing gonads when sex determination normally occurs in mice.

Dysregulation of cotranscriptional alternative splicing underlies CHARGE syndrome.

CHARGE syndrome-which stands for coloboma of the eye, heart defects, atresia of choanae, retardation of growth/development, genital abnormalities, and ear anomalies-is a severe developmental disorder with wide phenotypic variability, caused mainly by mutations in (chromodomain helicase DNA-binding protein 7), known to encode a chromatin remodeler. The genetic lesions responsible for mutation-negative cases are unknown, at least in part because the pathogenic mechanisms underlying CHARGE syndrome remain poorly defined. Here, we report the characterization of a mouse model for mutation-negative cases of CHARGE syndrome generated by insertional mutagenesis of (family with sequence similarity 172, member A).