Light is an important environmental cue that affects physiology and development of Neurospora crassa. The light-sensing transcription factor (TF) WCC, which consists of the GATA-family TFs WC1 and WC2, is required for light-dependent transcription. SUB1, another GATA-family TF, is not a photoreceptor but has also been implicated in light-inducible gene expression. To assess regulation and organization of the network of light-inducible genes, we analyzed the roles of WCC and SUB1 in light-induced transcription and nucleosome remodeling. We show that SUB1 co-regulates a fraction of light-inducible genes together with the WCC. WCC induces nucleosome eviction at its binding sites. Chromatin remodeling is facilitated by SUB1 but SUB1 cannot activate light-inducible genes in the absence of WCC. We identified FF7, a TF with a putative O-acetyl transferase domain, as an interaction partner of SUB1 and show their cooperation in regulation of a fraction of light-inducible and a much larger number of non light-inducible genes. Our data suggest that WCC acts as a general switch for light-induced chromatin remodeling and gene expression. SUB1 and FF7 synergistically determine the extent of light-induction of target genes in common with WCC but have in addition a role in transcription regulation beyond light-induced gene expression.

The "blepharophimosis-mental retardation" syndromes (BMRS) consist of a group of clinically and genetically heterogeneous congenital malformation syndromes, where short palpebral fissures and intellectual disability associate with a distinct set of other morphological features. Kaufman oculocerebrofacial syndrome represents a rare and recently reevaluated entity within the BMR syndromes and is caused by biallelic mutations of UBE3B. Affected individuals typically show microcephaly, impaired somatic growth, gastrointestinal and genitourinary problems, ectodermal anomalies and a characteristic face with short, upslanted palpebral fissures, depressed nasal bridge. and anteverted nares. Here we present four patients with five novel UBE3B mutations and propose the inclusion of clinical features to the characteristics of Kaufman oculocerebrofacial syndrome, including prominence of the cheeks and limb anomalies.

Mutations of the histone acetyltransferase-encoding KAT6B gene cause the Say-Barber-Biesecker/Young-Simpson (SBBYS) type of blepharophimosis-"mental retardation" syndromes and the more severe genitopatellar syndrome. The SBBYS syndrome-causing mutations are clustered in the large exon 18 of KAT6B and almost exclusively lead to predicted protein truncation. An atypical KAT6B mutation, a de novo synonymous variant located in exon 16 (c.3147G>A, p.(Pro1049Pro)) was previously identified in three unrelated patients. This exonic mutation was predicted in silico to cause protein truncation through aberrant splicing. Here, we report three additional unrelated children with typical SBBYS syndrome and the KAT6B c.3147G>A mutation. We show on RNA derived from patient blood that the mutation indeed induces aberrant splicing through the use of a cryptic exonic splice acceptor site created by the sequence variant. Our results thus identify the synonymous variant c.3147G>A as a splice site mutation and a mutational hot spot in SBBYS syndrome.