Pain perception has evolved as a warning mechanism to alert organisms to tissue damage and dangerous environments. In humans, however, undesirable, excessive or chronic pain is a common and major societal burden for which available medical treatments are currently suboptimal. New therapeutic options have recently been derived from studies of individuals with congenital insensitivity to pain (CIP). Here we identified 10 different homozygous mutations in PRDM12 (encoding PRDI-BF1 and RIZ homology domain-containing protein 12) in subjects with CIP from 11 families. Prdm proteins are a family of epigenetic regulators that control neural specification and neurogenesis. We determined that Prdm12 is expressed in nociceptors and their progenitors and participates in the development of sensory neurons in Xenopus embryos. Moreover, CIP-associated mutants abrogate the histone-modifying potential associated with wild-type Prdm12. Prdm12 emerges as a key factor in the orchestration of sensory neurogenesis and may hold promise as a target for new pain therapeutics.

Abstract:A recent outbreak of Zika virus in Brazil has led to a simultaneous increase in reports of neonatal microcephaly. Zika targets cerebral neural precursors, a cell population essential for cortical development, but the cause of this neurotropism remains obscure. Here we report that the neural RNA-binding protein Musashi-1 (MSI1) interacts with the Zika genome and enables viral replication. Zika infection disrupts the binding of MSI1 to its endogenous targets, thereby deregulating expression of factors implicated in neural stem cell function. We further show that MSI1 is highly expressed in neural progenitors of the human embryonic brain, and is mutated in individuals with autosomal recessive primary microcephaly. Selective MSI1 expression in neural precursors could therefore explain the exceptional vulnerability of these cells to Zika infection. Main text:Zika virus (ZIKV) recently emerged as a major public health risk because of its devastating effect on fetal neurodevelopment (1-3). ZIKV was first isolated in Uganda in 1947, and the virus subsequently spread through Asia, and from there to the Americas (4). A causal link between ZIKV infection and congenital brain malformations became apparent in 2016 following an outbreak in Brazil (1). Brazilian ZIKV is closely related to the Asian-lineage strain, which affected New Caledonia and French Polynesia, where cases of microcephaly were reported retrospectively (5).Intrauterine infections can impair neurodevelopment (6), but ZIKV is highly neurotropic and interferes specifically with fetal brain development causing microcephaly, cortical malformations and intracranial calcifications (7-10). We hypothesized that the singlestranded RNA flavivirus ZIKV may hijack RNA-binding factors present in the developing central nervous system (11). Host RNA-binding proteins are known to interact with untranslated regions (UTRs) to regulate replication, translation and stabilization of viral genomes (11). In silico analysis of the genomic RNA of the Brazilian ZIKV strain, PE243, revealed three consensus binding sites in the 3'UTR for the highly conserved Musashi family of RNA binding proteins, Musashi-1 (MSI1) and Musashi-2 (MSI2), both important translational regulators in stem cells (12)(13)(14)(15). Two sites were conserved between PE243 and the Ugandan MR766 strains (Sites 1, 2), whereas the third (Site 3) was found only in the Asian-lineage strains including PE243 ( Fig. 1A; Fig. S1A, B). By mapping these sites onto a predicted secondary structure of ZIKV 3'UTR, we found all the three to be present on stemloop structures, which are considered optimal for MSI binding (16,17). Moreover, a recent study revealed nucleotide substitutions proximal to Sites 1 and 2 in the Asian-lineage strains, which could indicate positive selection for MSI1 binding during ZIKV evolution (18).To address if the Musashi proteins interacted with ZIKV, we first tested their binding to ZIKV 3'UTR. RNA pull-downs identified binding of MSI1, but not MSI2, to the 3'UTR of PE243 (Fig. 1B) (15). Mutat...

Ufmylation is the post-translational modification of proteins through the addition of UFM1. Nahorksi et al. identify mutations in UFM1 and in UFC1, which encodes an enzyme required for ufmylation, in individuals with severe early-onset encephalopathy with progressive microcephaly. The findings suggest an essential role for ufmylation in human brain development.

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant condition characterised by the presence of facial fibrofolliculomas, pulmonary cysts which may be associated with spontaneous pneumothorax and renal tumours. Germline mutations in the gene Folliculin (FLCN) were first identified in BHD patients in 2002. In addition FLCN mutations have also been described in families with isolated primary spontaneous pneumothorax (PSP) and also familial clear cell renal carcinomas (FcRCC). We have established a locus-specific database based on the Leiden Open (source) Variation Database (LOVD) software. The version of the database contains 60 previously published mutations and 10 previously unpublished novel germline FLCN mutations. The mutations are comprised of deletions (44.3%), substitutions (35.7%), duplications (14.3%) and deletion/insertions (5.7%). The database is accessible online at http://www.lovd.nl/flcn

Birt-Hogg-Dube´ (BHD) syndrome is an autosomal dominant multisystem disorder with skin (fibrofolliculomas or trichodiscomas), lung (cysts and pneumothorax) and kidney (renal cell carcinoma) tumours. Although colorectal neoplasia was reported initially to be part of the BHD phenotype, some recent studies have not confirmed this association. We undertook a

Germline mutations in the FLCN gene cause Birt-Hogg-Dubé syndrome, familial spontaneous pneumothorax, or apparently nonsyndromic inherited RCC. The vast majority of reported FLCN mutations are predicted to result in a truncated/absent gene product and so infrequent missense and inframe-deletion (IFD) FLCN mutations might indicate critical functional domains. To investigate this hypothesis we (1) undertook an in silico evolutionary analysis of the FLCN sequence and (2) investigated in vitro the functional effects of naturally occurring FLCN missense/IFD mutations. The folliculin protein sequence evolved more slowly and was under stronger purifying selection than the average gene, most notably at a region between codons 100 and 230. Pathogenic missense and IFD FLCN mutations that impaired folliculin tumor suppressor function significantly disrupted the stability of the FLCN gene product but two missense substitutions initially considered to be putative mutations did not impair protein stability, growth suppression activity, or intracellular localization of folliculin. These findings are consistent with the distribution of FLCN mutations throughout the coding sequence, and suggest that multiple protein domains contribute to folliculin stability and tumor suppressor activity. In vitro assessment of protein stability and tumor suppressor activity provides a practical strategy for assessing the pathogenicity of potential FLCN mutations.

Inherited mutations in the folliculin (FLCN) gene cause the Birt-Hogg-Dubé syndrome of familial hair follicle tumours (fibrofolliculomas), lung cysts and kidney tumours. Though folliculin has features of a tumour suppressor, the precise function of the FLCN gene product is not well characterized. We identified plakophilin-4 (p0071) as a potential novel folliculin interacting protein by yeast two-hybrid analysis. We confirmed the interaction of folliculin with p0071 by co-immunoprecipitation studies and, in view of previous studies linking p0071 to the regulation of rho-signalling, cytokinesis and intercellular junction formation, we investigated the effect of cell folliculin status on p0071-related functions. Folliculin and p0071 partially co-localized at cell junctions and in mitotic cells, at the midbody during cytokinesis. Previously, p0071 has been reported to regulate RhoA signalling during cytokinesis and we found that folliculin deficiency was associated with increased expression and activity of RhoA and evidence of disordered cytokinesis. Treatment of folliculin-deficient cells with a downstream inhibitor of RhoA signalling (the ROCK inhibitor Y-27632) reversed the increased cell migration phenotype observed in folliculin-deficient cells. Deficiency of folliculin and of p0071 resulted in tight junction defects and mislocalization of E-cadherin in mouse inner medullary collecting duct-3 renal tubular cells. These findings suggest that aspects of folliculin tumour suppressor function are linked to interaction with p0071 and the regulation of RhoA signalling.

Congenital inability to feel pain is rare, but the identification of causative genes is translating into the development of novel analgesics. Nahorski et al. describe insensitivity to pain caused by mutations affecting the second clathrin heavy chain (CHC22), and reveal a role for CHC22 in pain and touch development.