Conserved intronic secondary structures with concealed branch sites regulate alternative splicing of poison exons.

Alternative splicing (AS) generates multiple RNA isoforms and increases the complexities of transcriptomes and proteomes. However, it remains unclear how RNA structures contribute to AS regulation. Here, we systematically search transcriptomes for secondary structures with concealed branch sites (BSs) in the alternatively spliced introns and predict thousands of them from six organisms, of which many are evolutionarily conserved. Intriguingly, a highly conserved stem-loop structure with concealed BSs is found in animal SF3B3 genes and colocalizes with a downstream poison exon (PE). Destabilization of this structure allows increased usage of the BSs and results in enhanced PE inclusion in human and Drosophila cells, leading to decreased expression of SF3B3. This structure is experimentally validated using an in-cell SHAPE-MaP assay. Through RNA interference screens of 28 RNA-binding proteins, we find that this stem-loop structure is sensitive to U2 factors. Furthermore, we find that SF3B3 also facilitates DNA repair and protects genome stability by enhancing interaction between ERCC6/CSB and arrested RNA polymerase II. Importantly, both Drosophila and human cells with the secondary structure mutated by genome editing exhibit altered DNA repair in vivo. This study provides a novel and common mechanism for AS regulation of PEs and reveals a physiological function of SF3B3 in DNA repair.

Phytophthora effector PSR1 hijacks the host pre-mRNA splicing machinery to modulate small RNA biogenesis and plant immunity.

Phytophthora effector PSR1 suppresses small RNA (sRNA)-mediated immunity in plants, but the underlying mechanism remains unknown. Here, we show that Phytophthora suppressor of RNA silencing 1 (PSR1) contributes to the pathogenicity of Phytophthora sojae and specifically binds to three conserved C-terminal domains of the eukaryotic PSR1-Interacting Protein 1 (PINP1). PINP1 encodes PRP16, a core pre-mRNA splicing factor that unwinds RNA duplexes and binds to primary microRNA transcripts and general RNAs. Intriguingly, PSR1 decreased both RNA helicase and RNA-binding activity of PINP1, thereby dampening sRNA biogenesis and RNA metabolism. The PSR1-PINP1 interaction caused global changes in alternative splicing (AS). A total of 5,135 genes simultaneously exhibited mis-splicing in both PSR1-overexpressing and PINP1-silenced plants. AS upregulated many mRNA transcripts that had their introns retained. The high occurrence of intron retention in AS-induced transcripts significantly promoted Phytophthora pathogen infection in Nicotiana benthamiana, and this might be caused by the production of truncated proteins. Taken together, our findings reveal a key role for PINP1 in regulating sRNA biogenesis and plant immunity.

Sex-lethal regulates back-splicing and generation of the sex-differentially expressed circular RNAs.

Conversely to canonical splicing, back-splicing connects the upstream 3' splice site (SS) with a downstream 5'SS and generates exonic circular RNAs (circRNAs) that are widely identified and have regulatory functions in eukaryotic gene expression. However, sex-specific back-splicing in Drosophila has not been investigated and its regulation remains unclear. Here, we performed multiple RNA analyses of a variety sex-specific Drosophila samples and identified over ten thousand circular RNAs, in which hundreds are sex-differentially and -specifically back-spliced. Intriguingly, we found that expression of SXL, an RNA-binding protein encoded by Sex-lethal (Sxl), the master Drosophila sex-determination gene that is only spliced into functional proteins in females, promoted back-splicing of many female-differential circRNAs in the male S2 cells, whereas expression of a SXL mutant (SXLRRM) did not promote those events. Using a monoclonal antibody, we further obtained the transcriptome-wide RNA-binding sites of SXL through PAR-CLIP. After splicing assay of mini-genes with mutations in the SXL-binding sites, we revealed that SXL-binding on flanking exons and introns of pre-mRNAs facilitates back-splicing, whereas SXL-binding on the circRNA exons inhibits back-splicing. This study provides strong evidence that SXL has a regulatory role in back-splicing to generate sex-specific and -differential circRNAs, as well as in the initiation of sex-determination cascade through canonical forward-splicing.

Two oppositely-charged sf3b1 mutations cause defective development, impaired immune response, and aberrant selection of intronic branch sites in Drosophila.

SF3B1 mutations occur in many cancers, and the highly conserved His662 residue is one of the hotspot mutation sites. To address effects on splicing and development, we constructed strains carrying point mutations at the corresponding residue His698 in Drosophila using the CRISPR-Cas9 technique. Two mutations, H698D and H698R, were selected due to their frequent presence in patients and notable opposite charges. Both the sf3b1-H698D and-H698R mutant flies exhibit developmental defects, including less egg-laying, decreased hatching rates, delayed morphogenesis and shorter lifespans. Interestingly, the H698D mutant has decreased resistance to fungal infection, while the H698R mutant shows impaired climbing ability. Consistent with these phenotypes, further analysis of RNA-seq data finds altered expression of immune response genes and changed alternative splicing of muscle and neural-related genes in the two mutants, respectively. Expression of Mef2-RB, an isoform of Mef2 gene that was downregulated due to splicing changes caused by H698R, partly rescues the climbing defects of the sf3b1-H698R mutant. Lariat sequencing reveals that the two sf3b1-H698 mutations cause aberrant selection of multiple intronic branch sites, with the H698R mutant using far upstream branch sites in the changed alternative splicing events. This study provides in vivo evidence from Drosophila that elucidates how these SF3B1 hotspot mutations alter splicing and their consequences in development and in the immune system.

Werner Salt as Nickel and Ammonia Source for Photochemical Synthesis of Primary Aryl Amines.

Cheap, stable and easy-to-handle Werner ammine salts have been known for more than a century; but they have been rarely used in organic synthesis. Herein, we report that the Werner hexammine complex [Ni(NH3 )6 ]Cl2 can be used as both a nitrogen and a catalytic nickel source that allow for the efficient amination of aryl chlorides in the presence of a catalytic amount of bipyridine ligand under the irradiation of 390-395 nm light without the need of any additional catalysts. More than 80 aryl chlorides, including more than 20 drug molecules, were aminated, demonstrating the practicality and generality of this method in synthetic chemistry. A slow NH3 release mechanism is in operation, obviating the problem of catalyst poisoning. Still interestingly, we show that the Werner salt can be easily recovered and reused, solving the problem of difficult recovery of transition metal nickel catalysts. The protocol thus provides an efficient new strategy for the synthesis of primary aryl amines.

Ni-Catalyzed Photochemical C-N Coupling of Amides with (Hetero)aryl Chlorides.

This paper reports a photochemical C-N coupling of abundant, but less reactive aryl chlorides, with structurally diverse primary and secondary amides by Ni-mediated without an external photocatalyst. Under the irradiation of light (390-395 nm) with a soluble organic amine as the base, the reaction allows for the successful transformation of (hetero)aryl chlorides to a wide range of N-aryl amides. More than 60 examples are shown, demonstrating the feasibility and applicability of this protocol in organic synthesis. Mechanic studies indicate that this amidation proceeds via a Ni(I)-Ni(III) catalytic cycle.

Potential G-quadruplexes within the Promoter Nuclease Hypersensitive Sites of the Heat-Responsive Genes in Rice.

G-quadruplexes (G4s) have been shown to be involved in the regulation of multiple cellular processes. Exploring putative G4-forming sequences (PQSs) in heat-responsive genes of rice and their folding structures under different conditions will help to understand the mechanism in response to heat stress. In this work, we discovered a prevalence of PQSs in nuclease hypersensitive sites within the promoters of heat-responsive genes. Moreover, 50 % of the searched G3 PQSs ((G3+ L1-7 )3+ G3+ ) locate in heat shock transcription factors. Circular dichroism spectroscopy, thermal difference spectroscopy, and UV melting analysis demonstrated the representative PQSs could adopt stable G4s at physiological temperature and potassium concentration. These PQSs were able to stall Klenow fragment (KF) DNA polymerase by the formation of G4s. However, the G4s with Tm values around 50-60 °C could be increasingly unwound by KF with the increase of temperatures from 25 to 50 °C, implying that these G4s could sense the changes in temperature by structural switch. This work offers fresh clues to understanding the potential of G4-involved functions of PQSs and the molecular events in plants in response to heat stress.

General Method for the Amination of Aryl Halides with Primary and Secondary Alkyl Amines via Nickel Photocatalysis.

The Buchwald-Hartwig C-N coupling reaction has been ranked as one of the 20 most frequently used reactions in medicinal chemistry. Owing to its much lower cost and higher reactivity toward less reactive aryl chlorides than palladium, the C-N coupling reaction catalyzed by Ni-based catalysts has received a great deal of attention. However, there appear to be no universal, practical Ni catalytic systems so far that could enable the coupling of electron-rich and electron-poor aryl halides with both primary and secondary alkyl amines. In this study, it is reported that a Ni(II)-bipyridine complex catalyzes efficient C-N coupling of aryl chlorides and bromides with various primary and secondary alkyl amines under direct excitation with light. Intramolecular C-N coupling is also demonstrated. The feasibility and applicability of the protocol in organic synthesis is attested by more than 200 examples.

Prp5-Spt8/Spt3 interaction mediates a reciprocal coupling between splicing and transcription.

Transcription and pre-mRNA splicing are coupled to promote gene expression and regulation. However, mechanisms by which transcription and splicing influence each other are still under investigation. The ATPase Prp5p is required for pre-spliceosome assembly and splicing proofreading at the branch-point region. From an open UV mutagenesis screen for genetic suppressors of prp5 defects and subsequent targeted testing, we identify components of the TBP-binding module of the Spt-Ada-Gcn5 Acetyltransferase (SAGA) complex, Spt8p and Spt3p. Spt8Δ and spt3Δ rescue the cold-sensitivity of prp5-GAR allele, and prp5 mutants restore growth of spt8Δ and spt3Δ strains on 6-azauracil. By chromatin immunoprecipitation (ChIP), we find that prp5 alleles decrease recruitment of RNA polymerase II (Pol II) to an intron-containing gene, which is rescued by spt8Δ. Further ChIP-seq reveals that global effects on Pol II-binding are mutually rescued by prp5-GAR and spt8Δ. Inhibited splicing caused by prp5-GAR is also restored by spt8Δ. In vitro assays indicate that Prp5p directly interacts with Spt8p, but not Spt3p. We demonstrate that Prp5p's splicing proofreading is modulated by Spt8p and Spt3p. Therefore, this study reveals that interactions between the TBP-binding module of SAGA and the spliceosomal ATPase Prp5p mediate a balance between transcription initiation/elongation and pre-spliceosome assembly.

Detection of G-Quadruplex Structures Formed by G-Rich Sequences from Rice Genome and Transcriptome Using Combined Probes.

Putative G-quadruplex (G4) forming sequences (PQS) are highly prevalent in the genome and transcriptome of various organisms and are considered as potential regulation elements in many biological processes by forming G4 structures. The formation of G4 structures highly depends on the sequences and the environment. In most cases, it is difficult to predict G4 formation by PQS, especially PQS containing G2 tracts. Therefore, the experimental identification of G4 formation is essential in the study of G4-related biological functions. Herein, we report a rapid and simple method for the detection of G4 structures by using a pair of complementary reporters, hemin and BMSP. This method was applied to detect G4 structures formed by PQS (DNA and RNA) searched in the genome and transcriptome of Oryza sativa. Unlike most of the reported G4 probes that only recognize part of G4 structures, the proposed method based on combined probes positively responded to almost all G4 conformations, including parallel, antiparallel, and mixed/hybrid G4, but did not respond to non-G4 sequences. This method shows potential for high-throughput identification of G4 structures in genome and transcriptome. Furthermore, BMSP was observed to drive some PQS to form more stable G4 structures or induce the G4 formation of some PQS that cannot form G4 in normal physiological conditions, which may provide a powerful molecular tool for gene regulation.

De novo sequencing and comparative transcriptome analysis of the male and hermaphroditic flowers provide insights into the regulation of flower formation in andromonoecious taihangia rupestris.

BACKGROUND: Taihangia rupestris, an andromonoecious plant species, bears both male and hermaphroditic flowers within the same individual. However, the establishment and development of male and hermaphroditic flowers in andromonoecious Taihangia remain poorly understood, due to the limited genetic and sequence information. To investigate the potential molecular mechanism in the regulation of Taihangia flower formation, we used de novo RNA sequencing to compare the transcriptome profiles of male and hermaphroditic flowers at early and late developmental stages. RESULTS: Four cDNA libraries, including male floral bud, hermaphroditic floral bud, male flower, and hermaphroditic flower, were constructed and sequenced by using the Illumina RNA-Seq method. Totally, 84,596,426 qualified Illumina reads were obtained and then assembled into 59,064 unigenes, of which 24,753 unigenes were annotated in the NCBI non-redundant protein database. In addition, 12,214, 7,153, and 8,115 unigenes were assigned into 53 Gene Ontology (GO) functional groups, 25 Clusters of Orthologous Group (COG) categories, and 126 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. By pairwise comparison of unigene abundance between the samples, we identified 1,668 differential expressed genes (DEGs), including 176 transcription factors (TFs) between the male and hermaphroditic flowers. At the early developmental stage, we found 263 up-regulated genes and 436 down-regulated genes expressed in hermaphroditic floral buds, while 844 up-regulated genes and 314 down-regulated genes were detected in hermaphroditic flowers at the late developmental stage. GO and KEGG enrichment analyses showed that a large number of DEGs were associated with a wide range of functions, including cell cycle, epigenetic processes, flower development, and biosynthesis of unsaturated fatty acid pathway. Finally, real-time quantitative PCR was conducted to validate the DEGs identified in the present study. CONCLUSION: In this study, transcriptome data of this rare andromonoecious Taihangia were reported for the first time. Comparative transcriptome analysis revealed the significant differences in gene expression profiles between male and hermaphroditic flowers at early and late developmental stages. The transcriptome data of Taihangia would be helpful to improve the understanding of the underlying molecular mechanisms in regulation of flower formation and unisexual flower establishment in andromonoecious plants.

Improvement of Efficiency in Kesterite Solar Cells by Intentionally Inserting a Thin MoS2 Layer into the Back Interface.

A Mo(S,Se)2 interfacial layer is formed inevitably and uncontrollably between the Mo electrode and Cu2ZnSn(S,Se)4 (CZTSSe) absorber during the selenization process, which significantly influences the performance of CZTSSe solar cells. In this work, an ultrathin MoS2 layer is intentionally inserted into Mo/CZTSSe to reduce the recombination and thus optimize the interface quality. It is revealed that the absorber exhibits a continuous and compact morphology with bigger grains and remarkably without pinholes across the surface or cross-sectional regions after MoS2 modification. Benefitting from this, the shunt resistance (RSh) of the device increased evidently from ∼395 to ∼634 Ω·cm2, and simultaneously, the reverse saturation current density (J0) realized an effective depression. As a result, the power conversion efficiency (PCE) of the MoS2-modified device reaches 9.64% via the optimization of the thickness of the MoS2 layer, indicating performance improvements with respect to the MoS2-free case. Furthermore, the main contribution to the performance improvement is derived and analyzed in detail from the increased RSh, decreased J0, and diode ideality factor. Our results suggest that the Mo/CZTSSe interface quality and performance of CZTSSe solar cells can be modulated and improved by appropriately designing and optimizing the thickness of the inserted MoS2 layer.

Minor Spliceosomal 65K/RNPC3 Interacts with ANKRD11 and Mediates HDAC3-Regulated Histone Deacetylation and Transcription.

RNA splicing is crucial in the multilayer regulatory networks for gene expression, making functional interactions with DNA- and other RNA-processing machineries in the nucleus. However, these established couplings are all major spliceosome-related; whether the minor spliceosome is involved remains unclear. Here, through affinity purification using Drosophila lysates, an interaction is identified between the minor spliceosomal 65K/RNPC3 and ANKRD11, a cofactor of histone deacetylase 3 (HDAC3). Using a CRISPR/Cas9 system, Deletion strains are constructed and found that both Dm65KΔ/Δ and Dmankrd11Δ/Δ mutants have reduced histone deacetylation at Lys9 of histone H3 (H3K9) and Lys5 of histone H4 (H4K5) in their heads, exhibiting various neural-related defects. The 65K-ANKRD11 interaction is also conserved in human cells, and the HsANKRD11 middle-uncharacterized domain mediates Hs65K association with HDAC3. Cleavage under targets and tagmentation (CUT&Tag) assays revealed that HsANKRD11 is a bridging factor, which facilitates the synergistic common chromatin-binding of HDAC3 and Hs65K. Knockdown (KD) of HsANKRD11 simultaneously decreased their common binding, resulting in reduced deacetylation of nearby H3K9. Ultimately, this study demonstrates that expression changes of many genes caused by HsANKRD11-KD are due to the decreased common chromatin-binding of HDAC3 and Hs65K and subsequently reduced deacetylation of H3K9, illustrating a novel and conserved coupling mechanism that links the histone deacetylation with minor spliceosome for the regulation of gene expression.

Roles of minor spliceosome in intron recognition and the convergence with the better understood major spliceosome.

Catalyzed by spliceosomes in the nucleus, RNA splicing removes intronic sequences from precursor RNAs in eukaryotes to generate mature RNA, which also significantly increases proteome complexity and fine-tunes gene expression. Most metazoans have two coexisting spliceosomes; the major spliceosome, which removes >99.5% of introns, and the minor spliceosome, which removes far fewer introns (only 770 at present have been predicted in the human genome). Both spliceosomes are large and dynamic machineries, each consisting of five small nuclear RNAs (snRNAs) and more than 100 proteins. However, the dynamic assembly, catalysis, and protein composition of the minor spliceosome are still poorly understood. With different splicing signals, minor introns are rare and usually distributed alone and flanked by major introns in genes, raising questions of how they are recognized by the minor spliceosome and how their processing deals with the splicing of neighboring major introns. Due to large numbers of introns and close similarities between the two machinery, cooperative, and competitive recognition by the two spliceosomes has been investigated. Functionally, many minor-intron-containing genes are evolutionarily conserved and essential. Mutations in the minor spliceosome exhibit a variety of developmental defects in plants and animals and are linked to numerous human diseases. Here, we review recent progress in the understanding of minor splicing, compare currently known components of the two spliceosomes, survey minor introns in a wide range of organisms, discuss cooperation and competition of the two spliceosomes in splicing of minor-intron-containing genes, and contributions of minor splicing mutations in development and diseases. This article is categorized under: RNA Processing > Processing of Small RNAs RNA Processing > Splicing Mechanisms RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.

Experimental Study on Creep-Recovery Behavior of Polyphosphoric Acid (PPA) Modified Asphalt Binders under Multiple Factors.

The polyphosphoric acid (PPA) modified asphalt binder is a potential choice as one of the pavement materials for its excellent high-temperature performance and low cost. To further analyze the influences of temperature and load on the service life of pavement from the perspective of deformation behavior, six kinds of asphalt binders with different PPA dosages were prepared for Multiple Stress Creep and Recovery (MSCR) tests at five temperature levels. The deformation behavior is investigated by basic deformation parameters, rheological simulation, and energy parameter changes. The results show that the percent recovery (R) drops sharply while non-recoverable creep compliance (Jnr) goes up slightly with the increase in temperature. Three-element model, composed by E1, η1, and η2, can be used to describe the creep behavior. PPA-modified asphalt binder exhibits nonlinear creep behavior, and the logarithmic model can simulate recovery behavior better than the power-law model. Stored energy and dissipated energy can characterize the change of energy in the creep process under different conditions and show a significant correlation to deformation parameters. It is concluded that the elastic component of asphalt binders is increased by PPA, which is beneficial to the improvement of the deformation resistance and recovery capacity of asphalt binders. The recommended dosage of PPA is 1.5%. This investigation is conducive to a better understanding of the deformation behavior of PPA-modified asphalt binders and provides a reference for its engineering applications.

An Alternatively Spliced Variant of METTL3 Mediates Tumor Suppression in Hepatocellular Carcinoma.

Many post-transcriptional mRNA processing steps play crucial roles in tumorigenesis and the progression of cancers, such as N6-methyladenosine (m6A) modification and alternative splicing. Upregulation of methyltransferase-like 3 (METTL3), the catalytic core of the m6A methyltransferase complex, increases m6A levels and results in significant effects on the progression of hepatocellular carcinoma (HCC). However, alternative splicing of METTL3 has not been fully investigated, and the functions of its splice variants remain unclear. Here, we analyzed both our and online transcriptomic data, obtaining 13 splice variants of METTL3 in addition to canonical full-length METTL3-A in HCC cell lines and tissues. Validated by RT-qPCR and Western blotting, we found that METTL3-D, one of the splice variants expressing a truncated METTL3 protein, exhibits higher levels than METTL3-A in normal human livers but lower levels than METTL3-A in HCC tumor tissues and cell lines. Further functional assays demonstrated that METTL3-D expression decreased cellular m6A modification, inhibited the proliferation, migration, and invasion of HCC cells, and was negatively associated with the malignancy of patient tumors, exhibiting functions opposite to those of full-length METTL3-A. This study demonstrates that the METTL3-D splice variant is a tumor suppressor that could potentially be used as a target for HCC therapy.

LncRNA Gm26917 regulates inflammatory response in macrophages by enhancing Annexin A1 ubiquitination in LPS-induced acute liver injury.

Long noncoding RNAs (lncRNAs) are defined as transcripts of more than 200 nucleotides that have little or no coding potential. LncRNAs function as key regulators in diverse physiological and pathological processes. However, the roles of lncRNAs in lipopolysaccharide (LPS)-induced acute liver injury (ALI) are still elusive. In this study, we report the roles of lncRNA Gm26917 induced by LPS in modulating liver inflammation. As key components of the innate immune system, macrophages play critical roles in the initiation, progression and resolution of ALI. Our studies demonstrated that Gm26917 localized in the cytoplasm of hepatic macrophages and globally regulated the expression of inflammatory genes and the differentiation of macrophages. In vivo study showed that lentivirus-mediated gene silencing of Gm26917 attenuated liver inflammation and protected mice from LPS-induced ALI. Furthermore, mechanistic study showed that the 3'-truncation of Gm26917 interacted with the N-terminus of Annexin A1, a negative regulator of the NF-κB signaling pathway. We also found that Gm26917 knockdown suppressed NF-κB activity by decreasing the ubiquitination of Annexin A1 and its interaction with NEMO. In addition, expression of Gm26917 in inflammatory macrophages was regulated by the transcription factor forkhead box M1 (FOXM1). LPS treatment dramatically increased the binding of FOXM1 to the promoter region of Gm26917 in macrophages. In summary, our findings suggest that lncRNA Gm26917 silencing protects against LPS-induced liver injury by regulating the TLR4/NF-κB signaling pathway in macrophages.

Comprehensive Identification and Alternative Splicing of Microexons in Drosophila.

Interrupted exons in the pre-mRNA transcripts are ligated together through RNA splicing, which plays a critical role in the regulation of gene expression. Exons with a length ≤ 30 nt are defined as microexons that are unique in identification. However, microexons, especially those shorter than 8 nt, have not been well studied in many organisms due to difficulties in mapping short segments from sequencing reads. Here, we analyzed mRNA-seq data from a variety of Drosophila samples with a newly developed bioinformatic tool, ce-TopHat. In addition to the Flybase annotated, 465 new microexons were identified. Differentially alternatively spliced (AS) microexons were investigated between the Drosophila tissues (head, body, and gonad) and genders. Most of the AS microexons were found in the head and two AS microexons were identified in the sex-determination pathway gene fruitless.

Defective minor spliceosomes induce SMA-associated phenotypes through sensitive intron-containing neural genes in Drosophila.

The minor spliceosome is evolutionarily conserved in higher eukaryotes, but its biological significance remains poorly understood. Here, by precise CRISPR/Cas9-mediated disruption of the U12 and U6atac snRNAs, we report that a defective minor spliceosome is responsible for spinal muscular atrophy (SMA) associated phenotypes in Drosophila. Using a newly developed bioinformatic approach, we identified a large set of minor spliceosome-sensitive splicing events and demonstrate that three sensitive intron-containing neural genes, Pcyt2, Zmynd10, and Fas3, directly contribute to disease development as evidenced by the ability of their cDNAs to rescue the SMA-associated phenotypes in muscle development, neuromuscular junctions, and locomotion. Interestingly, many splice sites in sensitive introns are recognizable by both minor and major spliceosomes, suggesting a new mechanism of splicing regulation through competition between minor and major spliceosomes. These findings reveal a vital contribution of the minor spliceosome to SMA and to regulated splicing in animals.

Antifungal effects of BiOBr nanosheets carrying surfactant cetyltrimethylammonium bromide.

BiOBr nanosheets are important photocatalytic nanomaterials. However, their biological effects remain to be explored. In this study, we investigated the antifungal effect of BiOBr nanosheets on Candida albicans. Strikingly, the nanosheets strongly inhibited the growth of C. albicans [IC50=(96±4.7) mg/L], hyphal development and biofilm formation. Compareed to the antifungal effect of the cationic surfactant cetyltrimethylammonium bromide, the inhibitory effect of the nanosheets on fungal pathogen was attributed to cetyltrimethylammonium bromide adsorbed by the nanosheets. Thermal gravity analysis and cetyltrimethylammonium bromide release experiment indicated that only 0.42% cetyltrimethylammonium bromide on BiOBr nanosheets was released. Taken together, this study uncovers the contribution of surfactant released from the nanosheets to their antifungal activity.