4.5SH RNA counteracts deleterious exonization of SINE B1 in mice.

4.5SH RNA is a highly abundant, small rodent-specific noncoding RNA that localizes to nuclear speckles enriched in pre-mRNA-splicing regulators. To investigate the physiological functions of 4.5SH RNA, we have created mutant mice that lack the expression of 4.5SH RNA. The mutant mice exhibited embryonic lethality, suggesting that 4.5SH RNA is an essential species-specific noncoding RNA in mice. RNA-sequencing analyses revealed that 4.5SH RNA protects the transcriptome from abnormal exonizations of the antisense insertions of the retrotransposon SINE B1 (asB1), which would otherwise introduce deleterious premature stop codons or frameshift mutations. Mechanistically, 4.5SH RNA base pairs with complementary asB1-containing exons via the target recognition region and recruits effector proteins including Hnrnpm via its 5' stem loop region. The modular organization of 4.5SH RNA allows us to engineer a programmable splicing regulator to induce the skipping of target exons of interest. Our results also suggest the general existence of splicing regulatory noncoding RNAs.

Chromatin modifier Hmga2 promotes adult hematopoietic stem cell function and blood regeneration in stress conditions.

The molecular mechanisms governing the response of hematopoietic stem cells (HSCs) to stress insults remain poorly defined. Here, we investigated effects of conditional knock-out or overexpression of Hmga2 (High mobility group AT-hook 2), a transcriptional activator of stem cell genes in fetal HSCs. While Hmga2 overexpression did not affect adult hematopoiesis under homeostasis, it accelerated HSC expansion in response to injection with 5-fluorouracil (5-FU) or in vitro treatment with TNF-α. In contrast, HSC and megakaryocyte progenitor cell numbers were decreased in Hmga2 KO animals. Transcription of inflammatory genes was repressed in Hmga2-overexpressing mice injected with 5-FU, and Hmga2 bound to distinct regions and chromatin accessibility was decreased in HSCs upon stress. Mechanistically, we found that casein kinase 2 (CK2) phosphorylates the Hmga2 acidic domain, promoting its access and binding to chromatin, transcription of anti-inflammatory target genes, and the expansion of HSCs under stress conditions. Notably, the identified stress-regulated Hmga2 gene signature is activated in hematopoietic stem progenitor cells of human myelodysplastic syndrome patients. In sum, these results reveal a TNF-α/CK2/phospho-Hmga2 axis controlling adult stress hematopoiesis.

Independent origins of fetal liver haematopoietic stem and progenitor cells.

Self-renewal and differentiation are tightly controlled to maintain haematopoietic stem cell (HSC) homeostasis in the adult bone marrow1,2. During fetal development, expansion of HSCs (self-renewal) and production of differentiated haematopoietic cells (differentiation) are both required to sustain the haematopoietic system for body growth3,4. However, it remains unclear how these two seemingly opposing tasks are accomplished within the short embryonic period. Here we used in vivo genetic tracing in mice to analyse the formation of HSCs and progenitors from intra-arterial haematopoietic clusters, which contain HSC precursors and express the transcription factor hepatic leukaemia factor (HLF). Through kinetic study, we observed the simultaneous formation of HSCs and defined progenitors-previously regarded as descendants of HSCs5-from the HLF+ precursor population, followed by prompt formation of the hierarchical haematopoietic population structure in the fetal liver in an HSC-independent manner. The transcription factor EVI1 is heterogeneously expressed within the precursor population, with EVI1hi cells being predominantly localized to intra-embryonic arteries and preferentially giving rise to HSCs. By genetically manipulating EVI1 expression, we were able to alter HSC and progenitor output from precursors in vivo. Using fate tracking, we also demonstrated that fetal HSCs are slowly used to produce short-term HSCs at late gestation. These data suggest that fetal HSCs minimally contribute to the generation of progenitors and functional blood cells before birth. Stem cell-independent pathways during development thus offer a rational strategy for the rapid and simultaneous growth of tissues and stem cell pools.

Morc1 reestablishes H3K9me3 heterochromatin on piRNA-targeted transposons in gonocytes.

To maintain fertility, male mice re-repress transposable elements (TEs) that were de-silenced in the early gonocytes before their differentiation into spermatogonia. However, the mechanism of TE silencing re-establishment remains unknown. Here, we found that the DNA-binding protein Morc1, in cooperation with the methyltransferase SetDB1, deposits the repressive histone mark H3K9me3 on a large fraction of activated TEs, leading to heterochromatin. Morc1 also triggers DNA methylation, but TEs targeted by Morc1-driven DNA methylation only slightly overlapped with those repressed by Morc1/SetDB1-dependent heterochromatin formation, suggesting that Morc1 silences TEs in two different manners. In contrast, TEs regulated by Morc1 and Miwi2, the nuclear PIWI-family protein, almost overlapped. Miwi2 binds to PIWI-interacting RNAs (piRNAs) that base-pair with TE mRNAs via sequence complementarity, while Morc1 DNA binding is not sequence specific, suggesting that Miwi2 selects its targets, and then, Morc1 acts to repress them with cofactors. A high-ordered mechanism of TE repression in gonocytes has been identified.

Dual functions of angiopoietin-like protein 2 signaling in tumor progression and anti-tumor immunity.

Angiopoietin-like protein 2 (ANGPTL2) is a secreted glycoprotein homologous to angiopoietins. Previous studies suggest that tumor cell-derived ANGPTL2 has tumor-promoting function. Here, we conducted mechanistic analysis comparing ANGPTL2 function in cancer progression in a murine syngeneic model of melanoma and a mouse model of translocation renal cell carcinoma (tRCC). ANGPTL2 deficiency in tumor cells slowed tRCC progression, supporting a tumor-promoting role. However, systemic ablation of ANGPTL2 accelerated tRCC progression, supporting a tumor-suppressing role. The syngeneic model also demonstrated a tumor-suppressing role of ANGPTL2 in host tumor microenvironmental cells. Furthermore, the syngeneic model showed that PDGFRα+ fibroblasts in the tumor microenvironment express abundant ANGPTL2 and contribute to tumor suppression. Moreover, host ANGPTL2 facilitates CD8+ T-cell cross-priming and enhances anti-tumor immune responses. Importantly, ANGPTL2 activates dendritic cells through PIR-B-NOTCH signaling and enhances tumor vaccine efficacy. Our study provides strong evidence that ANGPTL2 can function in either tumor promotion or suppression, depending on what cell type it is expressed in.

The polyol pathway is an evolutionarily conserved system for sensing glucose uptake.

Cells must adjust the expression levels of metabolic enzymes in response to fluctuating nutrient supply. For glucose, such metabolic remodeling is highly dependent on a master transcription factor ChREBP/MondoA. However, it remains elusive how glucose fluctuations are sensed by ChREBP/MondoA despite the stability of major glycolytic pathways. Here, we show that in both flies and mice, ChREBP/MondoA activation in response to glucose ingestion involves an evolutionarily conserved glucose-metabolizing pathway: the polyol pathway. The polyol pathway converts glucose to fructose via sorbitol. It has been believed that this pathway is almost silent, and its activation in hyperglycemic conditions has deleterious effects on human health. We show that the polyol pathway regulates the glucose-responsive nuclear translocation of Mondo, a Drosophila homologue of ChREBP/MondoA, which directs gene expression for organismal growth and metabolism. Likewise, inhibition of the polyol pathway in mice impairs ChREBP's nuclear localization and reduces glucose tolerance. We propose that the polyol pathway is an evolutionarily conserved sensing system for glucose uptake that allows metabolic remodeling.

Multiple genes in the Pate5-13 genomic region contribute to ADAM3 processing†.

Sperm proteins undergo post-translational modifications during sperm transit through the epididymis to acquire fertilizing ability. We previously reported that the genomic region coding Pate family genes is key to the proteolytic processing of the sperm membrane protein ADAM3 and male fertility. This region contains nine Pate family genes (Pate5-13), and two protein-coding genes (Gm27235 and Gm5916), with a domain structure similar to Pate family genes. Therefore, in this study, we aimed to identify key factors by narrowing the genomic region. We generated three knockout (KO) mouse lines using CRISPR/Cas9: single KO mice of Pate10 expressed in the caput epididymis; deletion KO mice of six caput epididymis-enriched genes (Pate5-7, 13, Gm27235, and Gm5916) (Pate7-Gm5916 KO); and deletion KO mice of four genes expressed in the placenta and epididymis (Pate8, 9, 11, and 12) (Pate8-12 KO). We observed that the fertility of only Pate7-Gm5916 KO males was reduced, whereas the rest remained unaffected. Furthermore, when the caput epididymis-enriched genes, Pate8 and Pate10 remained in Pate7-Gm5916 KO mice were independently deleted, both KO males displayed more severe subfertility due to a decrease in mature ADAM3 and a defect in sperm migration to the oviduct. Thus, our data showed that multiple caput epididymis-enriched genes within the region coding Pate5-13 cooperatively function to ensure male fertility in mice.

A gain-of-function mutation in microRNA 142 is sufficient to cause the development of T-cell leukemia in mice.

MicroRNAs (miRNAs) play a crucial role in regulating gene expression. MicroRNA expression levels fluctuate, and point mutations and methylation occur in cancer cells; however, to date, there have been no reports of carcinogenic point mutations in miRNAs. MicroRNA 142 (miR-142) is frequently mutated in patients with follicular lymphoma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia (CLL), and acute myeloid leukemia/myelodysplastic syndrome (AML/MDS). To understand the role of miR-142 mutation in blood cancers, the CRISPR-Cas9 system was utilized to successfully generate miR-142-55A>G mutant knock-in (Ki) mice, simulating the most frequent mutation in patients with miR-142 mutated AML/MDS. Bone marrow cells from miR-142 mutant heterozygous Ki mice were transplanted, and we found that the miR-142 mutant/wild-type cells were sufficient for the development of CD8+ T-cell leukemia in mice post-transplantation. RNA-sequencing analysis in hematopoietic stem/progenitor cells and CD8+ T-cells revealed that miR-142-Ki/+ cells had increased expression of the mTORC1 activator, a potential target of wild-type miR-142-3p. Notably, the expression of genes involved in apoptosis, differentiation, and the inhibition of the Akt-mTOR pathway was suppressed in miR-142-55A>G heterozygous cells, indicating that these genes are repressed by the mutant miR-142-3p. Thus, in addition to the loss of function due to the halving of wild-type miR-142-3p alleles, mutated miR-142-3p gained the function to suppress the expression of distinct target genes, sufficient to cause leukemogenesis in mice.

A specific plasma amino acid profile in the Insulin2Q104del Kuma mice at the diabetic state and reversal from hyperglycemia.

The metabolites in the plasma serve as potential biomarkers of disease. We previously established an early-onset diabetes mouse model, Ins2+/Q104del Kuma mice, under a severe immune-deficient (Rag-2/Jak3 double-deficient in BALB/c) background. Here, we revealed the differences in plasma amino acid profiles between Kuma and the wild-type mice. We observed an early reduction in glucogenic and ketogenic amino acids, a late increase in branched-chain amino acids (BCAAs) and succinyl CoA-related amino acids, and a trend of increasing ketogenic amino acids in Kuma mice than in the wild-type mice. Kuma mice exhibited hyperglucagonemia at high blood glucose, leading to perturbations in plasma amino acid profiles. The reversal of blood glucose by islet transplantation normalized the increases of the BCAAs and several aspects of the altered metabolic profiles in Kuma mice. Our results indicate that the Kuma mice are a unique animal model to study the link between plasma amino acid profile and the progression of diabetes for monitoring the therapeutic effects.

LincRNA-p21 exon 1 expression correlates with Cdkn1a expression in vivo.

LincRNA-p21 is a long intergenic non-coding RNA (LincRNA) gene reported to activate the transcription of the adjacent Cdkn1a (p21) gene in cis. The importance of the enhancer elements in the LincRNA-p21 gene region has also been reported; however, the involvement of the LincRNA-p21 transcripts in regulating Cdkn1a in vivo is still unclear. In this study, we used a LincRNA-p21-trapped mouse line (LincRNA-p21Gt ) in which ßgeo was inserted into intron 1, and all enhancer elements were retained. In LincRNA-p21Gt/Gt mice, the transcription of LincRNA-p21 was repressed due to the ßgeo sequence, and the expression of exon 1 of LincRNA-p21 was restored through its deletion or replacement by another sequence, and Cdkn1a expression was also upregulated. Furthermore, regardless of the full-length transcripts, the expression of Cdkn1a correlated with the transcription of the exon 1 of LincRNA-p21. This result indicates that the LincRNA-p21 transcripts are not functional, but the transcriptional activity around exon 1 is important for Cdkn1a expression.

MicroRNA-142 Critically Regulates Group 2 Innate Lymphoid Cell Homeostasis and Function.

Innate lymphoid cells are central to the regulation of immunity at mucosal barrier sites, with group 2 innate lymphoid cells (ILC2s) being particularly important in type 2 immunity. In this study, we demonstrate that microRNA(miR)-142 plays a critical, cell-intrinsic role in the homeostasis and function of ILC2s. Mice deficient for miR-142 expression demonstrate an ILC2 progenitor-biased development in the bone marrow, and along with peripheral ILC2s at mucosal sites, these cells display a greatly altered phenotype based on surface marker expression. ILC2 proliferative and effector functions are severely dysfunctional following Nippostrongylus brasiliensis infection, revealing a critical role for miR-142 isoforms in ILC2-mediated immune responses. Mechanistically, Socs1 and Gfi1 expression are regulated by miR-142 isoforms in ILC2s, impacting ILC2 phenotypes as well as the proliferative and effector capacity of these cells. The identification of these novel pathways opens potential new avenues to modulate ILC2-dependent immune functions.

Meiotic cohesins mediate initial loading of HORMAD1 to the chromosomes and coordinate SC formation during meiotic prophase.

During meiotic prophase, sister chromatids are organized into axial element (AE), which underlies the structural framework for the meiotic events such as meiotic recombination and homolog synapsis. HORMA domain-containing proteins (HORMADs) localize along AE and play critical roles in the regulation of those meiotic events. Organization of AE is attributed to two groups of proteins: meiotic cohesins REC8 and RAD21L; and AE components SYCP2 and SYCP3. It has been elusive how these chromosome structural proteins contribute to the chromatin loading of HORMADs prior to AE formation. Here we newly generated Sycp2 null mice and showed that initial chromatin loading of HORMAD1 was mediated by meiotic cohesins prior to AE formation. HORMAD1 interacted not only with the AE components SYCP2 and SYCP3 but also with meiotic cohesins. Notably, HORMAD1 interacted with meiotic cohesins even in Sycp2-KO, and localized along cohesin axial cores independently of the AE components SYCP2 and SYCP3. Hormad1/Rad21L-double knockout (dKO) showed more severe defects in the formation of synaptonemal complex (SC) compared to Hormad1-KO or Rad21L-KO. Intriguingly, Hormad1/Rec8-dKO but not Hormad1/Rad21L-dKO showed precocious separation of sister chromatid axis. These findings suggest that meiotic cohesins REC8 and RAD21L mediate chromatin loading and the mode of action of HORMAD1 for synapsis during early meiotic prophase.

Gene trapping reveals a new transcriptionally active genome element: The chromosome-specific clustered trap region.

Nearly half of the human genome consists of repetitive sequences such as long interspersed nuclear elements. The relationship between these repeating sequences and diseases has remained unclear. Gene trapping is a useful technique for disrupting a gene and expressing a reporter gene by using the promoter activity of the gene. The analysis of trapped genes revealed a new genome element-the chromosome-specific clustered trap (CSCT) region. For any examined sequence within this region, an equivalent was found using the BLAT of the University of California, Santa Cruz (UCSC) Genome Browser. CSCT13 mapped to chromosome 13 and contained only three genes. To elucidate its in vivo function, the whole CSCT13 region (1.6 Mbp) was deleted using the CRISPR/Cas9 system in mouse embryonic stem cells, and subsequently, a CSCT13 knockout mouse line was established. The rate of homozygotes was significantly lower than expected according to Mendel's laws. In addition, the number of offspring obtained by mating homozygotes was significantly smaller than that obtained by crossing controls. Furthermore, CSCT13 might have an effect on meiotic homologous recombination. This study identifies a transcriptionally active CSCT with an important role in mouse development.

ANGPTL2 expression in the intestinal stem cell niche controls epithelial regeneration and homeostasis.

The intestinal epithelium continually self-renews and can rapidly regenerate after damage. Dysregulation of intestinal epithelial homeostasis leads to severe inflammatory bowel disease. Additionally, aberrant signaling by the secreted protein angiopoietin-like protein 2 (ANGPTL2) causes chronic inflammation in a variety of diseases. However, little is known about the physiologic role of ANGPTL2 in normal tissue homeostasis and during wound repair following injury. Here, we assessed ANGPTL2 function in intestinal physiology and disease in vivo Although intestinal development proceeded normally in Angptl2-deficient mice, expression levels of the intestinal stem cell (ISC) marker gene Lgr5 decreased, which was associated with decreased transcriptional activity of ß-catenin in Angptl2-deficient mice. Epithelial regeneration after injury was significantly impaired in Angptl2-deficient relative to wild-type mice. ANGPTL2 was expressed and functioned within the mesenchymal compartment cells known as intestinal subepithelial myofibroblasts (ISEMFs). ANGPTL2 derived from ISEMFs maintained the intestinal stem cell niche by modulating levels of competing signaling between bone morphogenetic protein (BMP) and ß-catenin. These results support the importance of ANGPTL2 in the stem cell niche in regulating stemness and epithelial wound healing in the intestine.

Lung fibroblasts produce IL-33 in response to stimulation with retinoblastoma-binding protein 9 via production of prostaglandin E2.

Intestinal nematode infection induces pulmonary eosinophilia via IL-33, although the mechanism of pulmonary IL-33 induction remains unclear. Because nematode migration damages lungs, we speculated that lung-derived damage-associated molecular patterns (DAMPs) possess an IL-33-inducing activity (IL33ia). Indeed, intra-nasal administration of a lung extract induced IL-33 production in lungs. Additionally, lung extracts increased Il33 mRNA expression in primary lung fibroblasts. Proteomic analysis identified retinoblastoma-binding protein 9 (RBBP9) as a major DAMP with IL33ia. RBBP9 was originally discovered as a protein that provides cells with resistance to the growth inhibitory effect of transforming growth factor (TGF)-ß1. Here, we found that stimulation by RBBP9 induced primary fibroblasts to produce prostaglandin E2 (PGE2) that, in turn, induced fibroblasts to produce IL-33. RBBP9-activated fibroblasts expressed mRNAs of cyclooxygenase-2 (COX-2) and PGE2 synthase-1 that convert arachidonic acid to PGE2. Furthermore, they expressed PGE2 receptors E-prostanoid (EP) 2 and EP4. Thus, treatment with a COX-2 inhibitor or EP2 and/or EP4 receptor antagonists inhibited RBBP9-induced IL-33 production. Nematode infection induced pulmonary Il33 mRNA expression, which was inhibited by the COX-2 inhibitor or EP2 and EP4 antagonists, suggesting that nematode infection induced pulmonary Il33 mRNA via PGE2. RBBP9 was expressed constitutively in the lung in the steady state, which did not increase after nematode infection. Finally, we found that Rbbp9-deficient mice had a significantly diminished capacity to increase pulmonary Il33 mRNA expression following nematode infection. Thus, the PGE2-EP2/EP4 pathway activated by RBBP9 released from damaged lungs is important for pulmonary IL-33 production in nematode-infected animals.

Mammalian NSUN2 introduces 5-methylcytidines into mitochondrial tRNAs.

Post-transcriptional modifications in mitochondrial tRNAs (mt-tRNAs) play critical roles in mitochondrial protein synthesis, which produces respiratory chain complexes. In this study, we took advantage of mass spectrometric analysis to map 5-methylcytidine (m5C) at positions 48-50 in eight mouse and six human mt-tRNAs. We also confirmed the absence of m5C in mt-tRNAs isolated from Nsun2 knockout (KO) mice, as well as from NSUN2 KO human culture cells. In addition, we successfully reconstituted m5C at positions 48-50 of mt-tRNA in vitro with NSUN2 protein in the presence of S-adenosylmethionine. Although NSUN2 is predominantly localized to the nucleus and introduces m5C into cytoplasmic tRNAs and mRNAs, structured illumination microscopy clearly revealed NSUN2 foci inside mitochondria. These observations provide novel insights into the role of NSUN2 in the physiology and pathology of mitochondrial functions.

Crucial Role of AIM/CD5L in the Development of Glomerular Inflammation in IgA Nephropathy.

BACKGROUND: IgA nephropathy (IgAN) begins with aberrant IgA deposition in glomeruli, progresses to IgM/IgG/complement codeposition, and results in chronic inflammation and glomerular damage. However, the mechanism that drives such phlogogenic cascade has been unclear. Recently, apoptosis inhibitor of macrophage (AIM) protein was shown to modulate macrophages' function in various pathologic conditions, thereby profoundly affecting the progression of renal disorders, including AKI. A spontaneous IgAN model, grouped ddY (gddY) mouse, revealed the requirement of AIM for the overall inflammatory glomerular injury following IgA deposition. METHODS: We established an AIM-deficient IgAN model (AIM-/- gddY) using CRISPR/Cas9 and compared its phenotype with that of wild-type gddY with or without recombinant AIM administration. An IgA-deficient IgAN model (IgA-/- gddY) was also generated to further determine the role of AIM. RESULTS: In both human and murine IgAN, AIM colocalized with IgA/IgM/IgG in glomeruli, whereas control kidneys did not exhibit AIM deposition. Although AIM-/- gddY showed IgA deposition at levels comparable with those of wild-type gddY, they did not exhibit glomerular accumulation of IgM/IgG complements, CD45+ leukocyte infiltration, and upregulation of inflammatory/fibrogenic genes, indicating protection from glomerular lesions and proteinuria/hematuria. Recombinant AIM administration reconstituted the IgAN phenotype, resulting in IgM/IgG/complement IgA codeposition. Neither spontaneous IgM/IgG codeposition nor disease was observed in IgA-/- gddY mice. CONCLUSIONS: AIM may contribute to stable immune complex formation in glomeruli, thereby facilitating IgAN progression. Therefore, AIM deposition blockage or disassociation from IgM/IgG may present a new therapeutic target on the basis of its role in IgAN inflammation initiation.

Deletion in the Cobalamin Synthetase W Domain-Containing Protein 1 Gene Is associated with Congenital Anomalies of the Kidney and Urinary Tract.

BACKGROUND: Researchers have identified about 40 genes with mutations that result in the most common cause of CKD in children, congenital anomalies of the kidney and urinary tract (CAKUT), but approximately 85% of patients with CAKUT lack mutations in these genes. The anomalies that comprise CAKUT are clinically heterogenous, and thought to be caused by disturbances at different points in kidney development. However, identification of novel CAKUT-causing genes remains difficult because of their variable expressivity, incomplete penetrance, and heterogeneity. METHODS: We investigated two generations of a family that included two siblings with CAKUT. Although the parents and another child were healthy, the two affected siblings presented the same manifestations, unilateral renal agenesis and contralateral renal hypoplasia. To search for a novel causative gene of CAKUT, we performed whole-exome and whole-genome sequencing of DNA from the family members. We also generated two lines of genetically modified mice with a gene deletion present only in the affected siblings, and performed immunohistochemical and phenotypic analyses of these mice. RESULTS: We found that the affected siblings, but not healthy family members, had a homozygous deletion in the Cobalamin Synthetase W Domain-Containing Protein 1 (CBWD1) gene. Whole-genome sequencing uncovered genomic breakpoints, which involved exon 1 of CBWD1, harboring the initiating codon. Immunohistochemical analysis revealed high expression of Cbwd1 in the nuclei of the ureteric bud cells in the developing kidneys. Cbwd1-deficient mice showed CAKUT phenotypes, including hydronephrosis, hydroureters, and duplicated ureters. CONCLUSIONS: The identification of a deletion in CBWD1 gene in two siblings with CAKUT implies a role for CBWD1 in the etiology of some cases of CAKUT.

Topoisomerase IIIß Deficiency Induces Neuro-Behavioral Changes and Brain Connectivity Alterations in Mice.

Topoisomerase IIIß (Top3ß), the only dual-activity topoisomerase in mammals that can change topology of both DNA and RNA, is known to be associated with neurodevelopment and mental dysfunction in humans. However, there is no report showing clear associations of Top3ß with neuropsychiatric phenotypes in mice. Here, we investigated the effect of Top3ß on neuro-behavior using newly generated Top3ß deficient (Top3ß-/-) mice. We found that Top3ß-/- mice showed decreased anxiety and depression-like behaviors. The lack of Top3ß was also associated with changes in circadian rhythm. In addition, a clear expression of Top3ß was demonstrated in the central nervous system of mice. Positron emission tomography/computed tomography (PET/CT) analysis revealed significantly altered connectivity between many brain regions in Top3ß-/- mice, including the connectivity between the olfactory bulb and the cerebellum, the connectivity between the amygdala and the olfactory bulb, and the connectivity between the globus pallidus and the optic nerve. These connectivity alterations in brain regions are known to be linked to neurodevelopmental as well as psychiatric and behavioral disorders in humans. Therefore, we conclude that Top3ß is essential for normal brain function and behavior in mice and that Top3ß could be an interesting target to study neuropsychiatric disorders in humans.

WDR11-mediated Hedgehog signalling defects underlie a new ciliopathy related to Kallmann syndrome.

WDR11 has been implicated in congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome (KS), human developmental genetic disorders defined by delayed puberty and infertility. However, WDR11's role in development is poorly understood. Here, we report that WDR11 modulates the Hedgehog (Hh) signalling pathway and is essential for ciliogenesis. Disruption of WDR11 expression in mouse and zebrafish results in phenotypic characteristics associated with defective Hh signalling, accompanied by dysgenesis of ciliated tissues. Wdr11-null mice also exhibit early-onset obesity. We find that WDR11 shuttles from the cilium to the nucleus in response to Hh signalling. WDR11 regulates the proteolytic processing of GLI3 and cooperates with the transcription factor EMX1 in the induction of downstream Hh pathway gene expression and gonadotrophin-releasing hormone production. The CHH/KS-associated human mutations result in loss of function of WDR11. Treatment with the Hh agonist purmorphamine partially rescues the WDR11 haploinsufficiency phenotypes. Our study reveals a novel class of ciliopathy caused by WDR11 mutations and suggests that CHH/KS may be a part of the human ciliopathy spectrum.