Design, synthesis, and biological evaluation of pyrido[2,3-d]pyrimidin-7(8H)-one derivatives as potent USP1 inhibitors.

USP1 has emerged as a novel and potential target for drug discovery in single therapeutic agents or combination with chemotherapy and molecular targeted therapy. In this study, based on the disclosed structure of ML323 and KSQ-4279, we designed and synthesized a series of pyrido[2,3-d]pyrimidin-7(8H)-one derivatives as potent USP1 inhibitors by cyclization strategy and the systematic structure-activity relationship exploration was conducted. The representative compounds 1k, 1m and 2d displayed excellent USP1/UAF inhibition and exhibited strong antiproliferation effect in NCI-H1299 cells. Further flow cytometry analysis revealed that they could arrest breast cancer cells MDA-MB-436 in the S phase. Inhibition mechanism study of compound 1m indicated these derivatives acted as reversible and noncompetitive USP1 inhibitors. Of note, the combination of compound 1m with PARP inhibitor olaparib generated enhanced cell killing in olaparib-resistant MDA-MB-436/OP cells, and compound 1m exhibited excellent oral pharmacokinetic properties in mice. Overall, our efforts may provide a reliable basis for the development of novel USP1 inhibitor as a single therapeutic agent and in combination with PARP inhibitors.

Bioinformatics analysis on structure and function and expression vector construction of SARS-CoV-2 related protein TMPRSS2 / 中国药理学通报

Aim Human TMPRSS2 is a transmembrane serine protease.In this paper, the structure and func¬tion of the protein were systematically analyzed by bioinformatics, the codon was optimized and the pro- karvotie expression vector was constructed to explore the molecular mechanism of SARS-CoV-2 infecting host cells.Methods The recombinant expression vector pET-22b-TMPRSS2 was generated by molecular clo¬ning technology.The homology, functional sites, sub¬cellular localization, three-dimensional structure and evolutionary characteristics of TMPRSS2 protein were systematically analyzed by using analytical tools such as Protparam, NetPhos3.1, Blast, Clustal X2 and MEGA7.0.Results The prokarvotic expression plas- mid was constructed correctly; TMPRSS2 belongs to medium molecular weight protein, which is composed of 492 amino acid residues.The theoretical isoelectric point is 8.12, the molecular extinction coefficient is 118 145 L • mol~1 • cm"1 , and the half-life is 30 h; TMPRSS2 has 15 potential glycosylation sites and 49 possible phosphorylation sites.It is a transmembrane hydrophilie protein without signal sequenee.In addi¬tion, the protein has 13 potential B-cell epitopes and 7 T-eell epitopes.Seeondarv structure analysis showed that random coil accounted for the highest proportion of TMPRSS2 protein ( 0.453 3) , followed by extended strand (0.252 0).Sequence comparison and evolu¬tionary analysis showed that the highest sequence con¬sistency and closest genetic relationship with human TMPRSS2 was Pan troglodytes, followed by gorilla.Conclusions Human-derived TMPRSS2 protein is ev- olutionarilv conserved and functionally important.Hie results of this study can help to reveal the structure and mechanism of action of TMPRSS2 protein, provide ide¬as for the diagnosis and treatment of COYID-19, and accelerate the research and development process of new drugs targeting TMPRSS2 protein.

Interesting new Chinese species of Leptoceridae and Odontoceridae (Insecta: Trichoptera) from several recent collecting efforts.

In contravention of Article 16.4.2 of the International Code of Zoological Nomenclature (International Trust for Zoological Nomenclature 1999), the repository for the holotypes of these species was not mentioned by Yang et al. (2020), such that the names proposed for these species are presently nomina nuda.

Interesting new Chinese species of Leptoceridae and Odontoceridae (Insecta: Trichoptera) from several recent collecting efforts.

Nine new species of caddisflies are described from southeastern and central China, including 7 species of Leptoceridae: Ceraclea (Ceraclea) megalophyllon Yang Morse sp. n., C. (Athripsodina) aerumnula Yang Morse sp. n., C. (Ath.) lamellata Yang Hu sp. n., Oecetis (Oecetis) discedens Yang Morse sp. n., Oe. (Pleurograpta) spinellosa Yang Hu sp. n., Setodes charax Yang Morse sp. n., and S. scutatus Yang Morse sp. n. Two species of Odontoceridae also are included: Phraepsyche acuminata Yang Morse sp. n. and Psilotreta longicornis Yang Morse sp. n. The male genitalia of all species and female genitalia of C. megalophylla, C. lamellata, Oecetis discedens, and Oe. spinellosa are figured.

Recent Development on Controlled Synthesis of Metal Sulfides Hollow Nanostructures via Hard Template Engaged Strategy: A Mini-Review.

In this mini-review, we highlighted the recent progresses in the controlled synthesis of metal sulfides hollow nanostructures via hard template technique. After a brief introduction about the formation mechanism of the inorganic hollow nanostructures via hard template technique, the discussions primarily focused on the emerging development of metal sulfides hollow nanostructures. Various synthetic strategies were summarized concerning the use of the hard template engaged strategies to fabricate various metal sulfides hollow nanostructures, such as hydrothermal method, solvothermal method, ion-exchange, sulfidation or calcination etc. Finally, the perspectives and summaries have been presented to demonstrate that a facile synthetic technique would be widely used to fabricate metal sulfides hollow nanostructures with multi-shells and components.

[Application of High Resolution Melting Curve Analysis in Detection of SLC4A1 Gene Mutation in Patients with Hereditary Spherocytosis].

OBJECTIVE: To investigate the feasibility and clinical significance of high resolution melting(HRM) curve analysis to detect SLC4A1 gene D38A and K56E mutations in the patients with hereditary spherocytosis(HS). METHODS: Peripheral blood was collected from 23 cases of HS for routine tests and their genomic DNA was extracted by routine technique. Specific primers of mutation sites D38A and K56E of SLC4A1 gene were designed. The HRM method was used to analyze all the samples, and then the results of HRM were verified with DNA sequencing technology. RESULTS: Among 23 specimens of HS patients, 6 cases of heterozygous mutant gene were detected by HRM technology, including 3 cases of D38A mutation and 3 cases of K56E mutation, which were confirmed by DNA sequencing. CONCLUSION: The HRM technology can correctly detect 2 common mutation sites including D38A and K56E in SLC4A1 gene in an efficient, fast, and reliable way, which not only can be used for clinical diagnosis, but also expected to be a new method for clinical researchers to define gene mutation spectrum in HS patients.

Eupatilin inhibits microglia activation and attenuates brain injury in intracerebral hemorrhage.

Inflammation serves a critical role in the pathophysiology of intracerebral hemorrhage (ICH)-induced brain injury. Eupatilin, a pharmacologically active flavone derived from Artemisia sp., has been reported to have antioxidant, anti-inflammatory, anti-allergic and antitumor activities. However, the effect of eupatilin in ICH has not been well studied. The aim of the present study was to investigate the effect of eupatilin on ICH-induced microglial inflammation. The MTT and Transwell migration assay results revealed that eupatilin significantly inhibited microglial migration. It also decreased the production of inflammatory cytokines in erythrocyte lysis-induced BV2 cells, as well as the level of intracellular reactive oxygen species. The anti-inflammatory mechanism of eupatilin was also investigated using ELISAs and western blotting and the results demonstrated that eupatilin was able to inhibit erythrocyte lysis-induced NF-κB activation in BV2 cells. Taken together, the results of the present study suggest that eupatilin serves neurological protective effects via inhibiting microglial inflammation, providing an experimental basis for the use of eupatilin as a therapeutic target for ICH.

Prior knowledge snake segmentation of ultrasound images denoised by J-divergence anisotropy diffusion.

BACKGROUND: Applying transrectal ultrasound to robot-assisted laparoscopic radical prostatectomy has attracted attention in recent years, and it is considered as a proper method to provide real-time subsurface anatomic features. A precise registration between the ultrasound equipment and robotic surgical system is necessary, which usually requires a fast and accurate recognition of the registration tool in the ultrasound image. METHODS: Tissue forceps are chosen as the registration tool. J-divergence anisotropy diffusion and prior knowledge snake segmentation are proposed for the automatic recognition of forceps in ultrasound images. RESULTS: Simulation, gel tissue phantom experiments and in vitro experiments are carried out. Several evaluation indices are calculated to compare results under different methods. CONCLUSIONS: The proposed methods are proved to be practicable, reliable and superior to existing ones, with reduced calculation time and higher accuracy.

Molecular Genetic Mechanisms of Hereditary Spherocytosis: Current Perspectives.

With the widespread use of genetic diagnostic technologies, many novel mutations have been identified in hereditary spherocytosis (HS)-related genes, including SPTA1, SPTB, ANK1, SLC4A1, and EPB42. However, mutations in HS-related genes are dispersed and nonspecific in the diagnosis of some HS patients, indicating significant heterogeneity in the molecular deficiency of HS. It is necessary to provide the molecular and genetic characteristics of these 5 genes for clinicians to examine HS. Here, we reviewed the recent proposed molecular genetic mechanisms of HS.

The effects of interleukin 2 and rAd-p53 as a treatment for glioblastoma.

Interleukin 2 (IL-2) is an anti-cancer cytokine that stimulates T cell propagation, triggering innate and adaptive immunity. IL-2 has been used for cancer therapy and has achieved curative effects. Recombinant adenovirus p53 injection (rAd­p53) is a gene therapeutic agent that may improve the prognosis of patients with glioblastoma (GBM). In the present study, the effect of combined IL­2 and rAd­p53 treatment was studied. The ability of IL­2 to stimulate immunoregulation and the ability of p53 to induce apoptosis for GBM was researched in the GBM tumor model. In addition, the activity of IL­2 was analyzed. The antitumor potential of IL­2 and rAd­p53 was studied using xenograph mice carrying GBM cells. Tumor­specific CD4+ and CD8+ T cells were also analyzed in the GBM­bearing models. The results demonstrated that IL­2 and rAd­p53 not only stimulated tumor­specific cytotoxic T­lymphocyte responses and increased regulatory CD4+ and cytotoxic CD8+ T cell proliferation, however additionally increased expression of apoptosis­associated genes. The treatment with IL­2 and rAd­p53 resulted in tumor regression and prolonged the survival of glioma­bearing mice. Taken together, a combination of IL­2 and rAd­p53 treatment combines the effects of immunotherapy and oncolytic therapy and may be a comprehensive therapeutic schedule for clinical application in future cancer therapies.

Application of High Resolution Melting Curve Analysis in Detection of SLC4A1 Gene Mutation in Patients with Hereditary Spherocytosis / 中国实验血液学杂志

OBJECTIVE@#To investigate the feasibility and clinical significance of high resolution melting(HRM) curve analysis to detect SLC4A1 gene D38A and K56E mutations in the patients with hereditary spherocytosis(HS).@*METHODS@#Peripheral blood was collected from 23 cases of HS for routine tests and their genomic DNA was extracted by routine technique. Specific primers of mutation sites D38A and K56E of SLC4A1 gene were designed. The HRM method was used to analyze all the samples, and then the results of HRM were verified with DNA sequencing technology.@*RESULTS@#Among 23 specimens of HS patients, 6 cases of heterozygous mutant gene were detected by HRM technology, including 3 cases of D38A mutation and 3 cases of K56E mutation, which were confirmed by DNA sequencing.@*CONCLUSION@#The HRM technology can correctly detect 2 common mutation sites including D38A and K56E in SLC4A1 gene in an efficient, fast, and reliable way, which not only can be used for clinical diagnosis, but also expected to be a new method for clinical researchers to define gene mutation spectrum in HS patients.

Overexpression of GRP75 inhibits inflammation in a rat model of intracerebral hemorrhage.

Glucose­regulated protein 75 (GRP75) is a member of the heat shock protein 70 family and previous studies have demonstrated that GRP75 is involved in diseases of the central nervous system. However, the biological function of GRP75 in intracerebral hemorrhage (ICH) remains to be clarified. Thus, the aim of the present study was to evaluate the effects of GRP75 in a rat model of ICH. Western blotting was used to detect the protein expression of GRP75, active caspase­3, Bax, Bcl­2, p­Akt and Akt in brain tissues following ICH. The levels of tumor necrosis factor­α (TNF­α) and interleukin (IL)­1ß were evaluated using ELISA assay. Expression of GRP75 mRNA and protein was demonstrated to be reduced in the brain tissues of rats with ICH compared with sham­operated rats. In addition, overexpression of GRP75 in brain tissues with ICH significantly inhibited the production of the inflammatory cytokines TNF­α and IL-1ß and increased Bcl­2/decreased Bax levels compared with ICH alone. Furthermore, overexpression of GRP75 in brain tissues with ICH resulted in significantly increased phosphorylation of Akt compared with ICH alone. Therefore, the present study demonstrated, for the first time to the best of our knowledge, significantly reduced GRP75 expression in brain tissues following ICH, and that overexpression of GRP75 inhibits inflammation and potentially inhibits neuronal apoptosis in a rat model of ICH. GRP75 may, therefore, represent a promising target in the treatment of ICH.

High-frequency repetitive transcranial magnetic stimulation combined with neuromuscular electrical stimulation for the treatment of poststroke dysphagia: a randomized controlled trial / 国际脑血管病杂志

Objective To assess the therapeutic effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) combined with neuromuscular electrical stimulation (NMES) on poststroke dysphagia.Methods A total of 90 patients with poststroke dysphagia were enrolled.They were randomly divided into either a NMES + rTMS group or a NMES + sham rTMS group (n =45 in each group).The Kuhota water drinking test and Standardized Swallowing Assessment (SSA) were used to assess the swallowing function.Results The scores of Kuhota water drinking test (F=82.001,P＜0.001) and the SSA (F =33.743,P ＜0.001) before treatment,treatment of one course,treatment of two courses,and at 3 months after treatment in the NMES + rTMS group had significant differences.Compared with before treatment,they were improved significantly for treatment of one course (P ＜0.01 and P ＜0.05,respectively),two courses (all P＜0.01),and at 3 months (all P＜0.01) after treatment.The scores of Kuhota water drinking test (F =53.647,P＜0.001) and the SSA (F=19.178,P＜0.001) in the NMES + sham rTMS group also had significant difference.Compared with before treatment,they had significant improvement for treatment of one course (all P ＜0.05),two courses (P ＜0.05 and P ＜0.01,respectively) and at 3 months (all P＜0.01)after treatment.The scores of Kuhota water drinking test for treatment of one course,two courses,and at 3 months after treatment (treatment of one course:t=2.217,P=0.02;treatment of two courses:t =2.406,P =0.019;at 3 months after treatment:t =2.128,P =0.037) and the SSA (treatment of one course:t =2.196,P =0.030,treatment of two courses:t =2.425,P =0.016;at 3 months after treatment:t =2.512,P=0.013) in the NMES + rTMS group were significantly better than those in the NMES + sham rTMS group.Conclusions High-frequency rTMS combined with NMES may significantly improve the swallowing function in patients with stroke.Its efficacy is superior to NMES.

Identification of differentially expressed microRNAs between Bacillus thuringiensis Cry1Ab-resistant and -susceptible strains of Ostrinia furnacalis.

The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), can develop strong resistance to Cry1Ab, the most widely commercialized Cry toxin for Bt maize worldwide. It is essential to understand the mechanism of resistance for management of this species, but information on the post-transcriptional regulation of Bt resistance in this target insect is limited. In the present study, RNA was extracted from the ACB in various larval stages (1-5 instar) from Cry1Ab-sensitive (ACB-BtS) and -resistant (ACB-AbR) strains, each of which included two biological replicates. Using Illumina sequencing, a total of 23,809,890 high-quality reads were collected from the four ACB libraries. The numbers of known microRNAs (miRNAs) were 302 and 395 for ACB-BtS and 268 and 287 for ACB-AbR. Using Mireap software, we identified 32 and 16 potential novel miRNAs for ACB-BtS and 18 and 22 for ACB-AbR. Among them, 21 known and 1 novel miRNAs had significantly different expression between ACB-BtS and ACB-AbR. Several miRNAs were observed to target potential Bt receptor genes, such as aminopeptidase N and cadherin-like protein. The glycosylphosphatidylinositol-anchor biosynthetic process and ABC transporters pathway were identified through Gene Ontology and KEGG pathway analysis of target genes of the differentially expressed miRNAs.

Transcriptome differences between Cry1Ab resistant and susceptible strains of Asian corn borer.

BACKGROUND: Asian corn borer (ACB), Ostrinia furnacalis (Guenée), is the major insect pest of maize in China and countries of East and Southeast Asia, the Pacific and Australasia. ACB can develop strong resistance to the transgenic Bt maize expressing Cry1Ab, the most widely commercialized Bt maize worldwide. However, the molecular basis for the resistance mechanisms of ACB to Cry1Ab remained unclear. Two biological replicates of the transcriptome of Bt susceptible (ACB-BtS) and Cry1Ab resistant (ACB-AbR) strains of ACB were sequenced using Solexa/Illumina RNA-Seq technology to identify Cry1Ab resistance-relevant genes. RESULTS: The numbers of unigenes for two biological replications were 63,032 and 53,710 for ACB-BtS and 57,770 and 54,468 for ACB-AbR. There were 35,723 annotated unigenes from ACB reads found by BLAST searching NCBI non-redundant, NCBI non-redundant nucleotide, Swiss-prot protein, Kyoto Encyclopedia of Genes and Genomes, Cluster of Orthologous Groups of proteins, and Gene Ontology databases. Based on the NOISeq method, 3,793 unigenes were judged to be differentially expressed between ACB-BtS and ACB-AbR. Cry1Ab resistance appeared to be associated with change in the transcription level of enzymes involved in growth regulation, detoxification and metabolic/catabolic process. Among previously described Bt toxin receptors, the differentially expressed unigenes associated with aminopeptidase N and chymotrypsin/trypsin were up-regulated in ACB-AbR. Whereas, other putative Cry receptors, cadherin-like protein, alkaline phosphatase, glycolipid, actin, V-type proton ATPase vatalytic, heat shock protein, were under-transcripted. Finally, GPI-anchor biosynthesis was found to be involved in the significantly enriched pathway, and all genes mapped to the pathway were substantially down-regulated in ACB-AbR. CONCLUSION: To our knowledge, this is the first comparative transcriptome study to discover candidate genes involved in ACB Bt resistance. This study identified differentially expressed unigenes related to general Bt resistance in ACB. The assembled, annotated transcriptomes provides a valuable genomic resource for further understanding of the molecular basis of ACB Bt resistance mechanisms.

Detecting the developmental toxicity of bFGF in the embryonic stem cell test using differential gene expression of differentiation-related genes.

Basic fibroblast growth factor (bFGF) is a mitogenic cytokine that can stimulate mesoderm-and neuroectoderm-originated cell proliferation. This study was performed to investigate the effects of bFGF on cell differentiation and the expression of specific markers at different embryonic developmental stages. We firstly evaluated the embryotoxic potential of bFGF in vitro using a modified EST protocol. Sequentially, we further investigated how bFGF impact the different tissue-special genes and proteins expressions during the differentiation of murine ES cells in vitro and attempt to reveal the effects of bFGF on differentiation processes. This analysis was focused on key tissue- and stage-specific genes involved in ectodermal, mesodermal, and endodermal differentiation, including ectodermal-specific gene Nestin, Oligo2 and Syn, mesodermal-specific gene MHC and MyoD, and endodermal-specific gene GATA6, TTR and ALB, as well as undifferentiated gene Sox-2 and Oct-4. The results demonstrate that bFGF could promote expression of ectodermal-specific genes and protein, but suppress the expressions of endoderm-specific and some mesoderm-specific gene and protein. A conclusion can be drawn that bFGF exhibits weak embryotoxicity and mainly promotes ES cell differentiation towards the ectodermal lineages but suppress differentiation into endoderm lineages. These opposing effects of bFGF on the embryonic development of the three germ layers may be related to its weak embryotoxic potential. More specifically, inhibition of expression of the endodermal-specific markers transthyretin (TTR), and albumin (ALB) by bFGF may be of more value in detecting the embryotoxic potential of bFGF.

Positive and negative regulation of Gli activity by Kif7 in the zebrafish embryo.

Loss of function mutations of Kif7, the vertebrate orthologue of the Drosophila Hh pathway component Costal2, cause defects in the limbs and neural tubes of mice, attributable to ectopic expression of Hh target genes. While this implies a functional conservation of Cos2 and Kif7 between flies and vertebrates, the association of Kif7 with the primary cilium, an organelle absent from most Drosophila cells, suggests their mechanisms of action may have diverged. Here, using mutant alleles induced by Zinc Finger Nuclease-mediated targeted mutagenesis, we show that in zebrafish, Kif7 acts principally to suppress the activity of the Gli1 transcription factor. Notably, we find that endogenous Kif7 protein accumulates not only in the primary cilium, as previously observed in mammalian cells, but also in cytoplasmic puncta that disperse in response to Hh pathway activation. Moreover, we show that Drosophila Costal2 can substitute for Kif7, suggesting a conserved mode of action of the two proteins. We show that Kif7 interacts with both Gli1 and Gli2a and suggest that it functions to sequester Gli proteins in the cytoplasm, in a manner analogous to the regulation of Ci by Cos2 in Drosophila. We also show that zebrafish Kif7 potentiates Gli2a activity by promoting its dissociation from the Suppressor of Fused (Sufu) protein and present evidence that it mediates a Smo dependent modification of the full length form of Gli2a. Surprisingly, the function of Kif7 in the zebrafish embryo appears restricted principally to mesodermal derivatives, its inactivation having little effect on neural tube patterning, even when Sufu protein levels are depleted. Remarkably, zebrafish lacking all Kif7 function are viable, in contrast to the peri-natal lethality of mouse kif7 mutants but similar to some Acrocallosal or Joubert syndrome patients who are homozygous for loss of function KIF7 alleles.

Targeted mutation of the talpid3 gene in zebrafish reveals its conserved requirement for ciliogenesis and Hedgehog signalling across the vertebrates.

Using zinc-finger nuclease-mediated mutagenesis, we have generated mutant alleles of the zebrafish orthologue of the chicken talpid3 (ta3) gene, which encodes a centrosomal protein that is essential for ciliogenesis. Animals homozygous for these mutant alleles complete embryogenesis normally, but manifest a cystic kidney phenotype during the early larval stages and die within a month of hatching. Elimination of maternally derived Ta3 activity by germline replacement resulted in embryonic lethality of ta3 homozygotes. The phenotype of such maternal and zygotic (MZta3) mutant zebrafish showed strong similarities to that of chick ta3 mutants: absence of primary and motile cilia as well as aberrant Hedgehog (Hh) signalling, the latter manifest by the expanded domains of engrailed and ptc1 expression in the somites, reduction of nkx2.2 expression in the neural tube, symmetric pectoral fins, cyclopic eyes and an ectopic lens. GFP-tagged Gli2a localised to the basal bodies in the absence of the primary cilia and western blot analysis showed that Gli2a protein is aberrantly processed in MZta3 embryos. Zygotic expression of ta3 largely rescued the effects of maternal depletion, but the motile cilia of Kupffer's vesicle remained aberrant, resulting in laterality defects. Our findings underline the importance of the primary cilium for Hh signaling in zebrafish and reveal the conservation of Ta3 function during vertebrate evolution.

Cranio-lenticulo-sutural dysplasia is caused by a SEC23A mutation leading to abnormal endoplasmic-reticulum-to-Golgi trafficking.

Cranio-lenticulo-sutural dysplasia (CLSD) is an autosomal recessive syndrome characterized by late-closing fontanels, sutural cataracts, facial dysmorphisms and skeletal defects mapped to chromosome 14q13-q21 (ref. 1). Here we show, using a positional cloning approach, that an F382L amino acid substitution in SEC23A segregates with this syndrome. SEC23A is an essential component of the COPII-coated vesicles that transport secretory proteins from the endoplasmic reticulum to the Golgi complex. Electron microscopy and immunofluorescence show that there is gross dilatation of the endoplasmic reticulum in fibroblasts from individuals affected with CLSD. These cells also exhibit cytoplasmic mislocalization of SEC31. Cell-free vesicle budding assays show that the F382L substitution results in loss of SEC23A function. A phenotype reminiscent of CLSD is observed in zebrafish embryos injected with sec23a-blocking morpholinos. Our observations suggest that disrupted endoplasmic reticulum export of the secretory proteins required for normal morphogenesis accounts for CLSD.

Genomic, cDNA and embryonic expression analysis of zebrafish IRF6, the gene mutated in the human oral clefting disorders Van der Woude and popliteal pterygium syndromes.

Van der Woude syndrome (VWS) and popliteal pterygium syndrome (PPS) are autosomal dominant clefting disorders recently discovered to be caused by mutations in the IRF6 (Interferon Regulatory Factor 6) gene. The IRF gene family consists of nine members encoding transcription factors that share a highly conserved helix-turn-helix DNA-binding domain and a less conserved protein-binding domain. Most IRFs regulate the expression of interferon-alpha and -beta after viral infection, but the function of IRF6 remains unknown. We have isolated a full-length zebrafish irf6 cDNA, which encodes a 492 amino acid protein that contains a Smad-IRF interaction motif and a DNA-binding domain. The zebrafish irf6 gene consists of eight exons and maps to linkage group 22 closest to marker unp1375. By in situ hybridization analysis of embryo whole-mounts and cryosections, we demonstrate that irf6 is first expressed as a maternal transcript. During gastrulation, irf6 expression was concentrated in the forerunner cells. From the bud stage to the 3-somite stage, irf6 expression was observed in the Kupffer's vesicle. No expression could be detected at the 6-somite and 10-somite stages. At the 14-somite stage, expression was detected in the otic placode. At the 17-somite stage, strong expression was also observed in the cloaca. During the pharyngula, hatch and larva periods up to 5 days post-fertilization, irf6 was expressed in the pharyngeal arches, olfactory and otic placodes, and in the epithelial cells of endoderm derived tissues. The latter tissues include the mouth, pharynx, esophagus, endodermal lining of swim bladder, liver, exocrine pancreas, and associated ducts. Overall, the zebrafish expression data are consistent with the observations of lip pits in VWS patients, as well as more recent reports of alae nasi, otitis media and sensorineural hearing loss documented in some patients.