Nuclear factor Y, a key player in neuronal gene regulation.

Establishing a functional nervous system is a complex process requiring tightly controlled gene expression programs to achieve the correct differentiation of distinct neuronal subtypes. The molecular programs required for neurons to acquire neuron-type-specific, and core pan-neuronal features mostly rely on sequence-specific transcription factors (TFs), which recognize and bind to cis-regulatory motifs present in the promoters of target genes. Recently, we investigated the role and mode of action of the NF-Y complex, a ubiquitously expressed transcriptional master regulator, in the Caenorhabditis elegans nervous system. We found that NFYA-1 is a pervasive regulator of neuron-specific and pan-neuronal gene batteries that are essential for neuronal development and function. Furthermore, we concluded that NFYA-1 acts cell autonomously by either directly binding to conserved motifs in target gene promoter regions or indirectly by regulating other transcriptional regulators to fine-tune gene expression. However, further studies are required to fully define the impact of the NF-Y complex on nervous system regulatory networks and how NF-Y coordinates with other TFs in this regard.

A CAM-Related NF-YB Transcription Factor Enhances Multiple Abiotic Stress Tolerance in Arabidopsis.

Abiotic stresses often occur simultaneously, and the tolerance mechanisms of plants to combined multiple abiotic stresses remain poorly studied. Extremophytes, adapted to abiotic stressors, might possess stress-adaptive or -responsive regulators that could enhance multiple abiotic stress resistance in crop plants. We identified an NF-YB transcription factor (TF) from the heat-tolerant obligate Crassulacean acid metabolism (CAM) plant, Kalanchoe fedtschenkoi, as a potential regulator of multiple abiotic stresses. The KfNF-YB3 gene was overexpressed in Arabidopsis to determine its role in multiple abiotic stress responses. Transgenic lines exhibited accelerated flowering time, increased biomass, larger rosette size, higher seed yield, and more leaves. Transgenic lines had higher germination rates under combined NaCl, osmotic, and water-deficit stress treatments compared to control plants. They also showed enhanced root growth and survival under simultaneous NaCl, osmotic, water-deficit, and heat stress conditions in vitro. Interestingly, potted transgenic lines had higher survival rates, yield, and biomass under simultaneous heat, water-deficit, and light stresses compared to control plants. Altogether, these results provide initial insights into the functions of a CAM-related TF and its potential roles in regulating multiple abiotic stress responses. The CAM abiotic stress-responsive TF-based approach appears to be an ideal strategy to enhance multi-stress resilience in crop plants.

CCAAT Promoter element regulates transgenerational expression of the MHC class I gene.

Transgenerational gene expression depends on both underlying DNA sequences and epigenetic modifications. The latter, which can result in transmission of variegated gene expression patterns across multiple generations without DNA alterations, has been termed epigenetic inheritance and has been documented in plants, worms, flies and mammals. Whereas transcription factors binding to cognate DNA sequence elements regulate gene expression, the molecular basis for epigenetic inheritance has been linked to histone and DNA modifications and non-coding RNA. Here we report that mutation of the CCAAT box promoter element abrogates NF-Y binding and disrupts the stable transgenerational expression of an MHC class I transgene. Transgenic mice with a mutated CCAAT box in the MHC class I transgene display variegated expression of the transgene among littermates and progeny in multiple independently derived transgenic lines. After 4 generations, CCAAT mutant transgenic lines derived from a single founder stably displayed distinct patterns of expression. Histone modifications and RNA polymerase II binding correlate with expression of CCAAT mutant transgenic lines, whereas DNA methylation and nucleosome occupancy do not. Mutation of the CCAAT box also results in changes to CTCF binding and DNA looping patterns across the transgene that correlate with expression status. These studies identify the CCAAT promoter element as a regulator of stable transgenerational gene expression such that mutation of the CCAAT box results in variegated transgenerational inheritance. Considering that the CCAAT box is present in 30% of eukaryotic promoters, this study provides insights into how fidelity of gene expression patterns is maintained through multiple generations.

Transcription factor OsNF-YC1 regulates grain size by coordinating the transcriptional activation of OsMADS1 in Oryza sativa L.

Grain weight, grain number per panicle, and the number of panicles are the three factors that determine rice (Oryza sativa L.) yield. Of these, grain weight, which not only directly determines rice yield but also influences appearance and quality, is often considered the most important for rice production. Here, we describe OsNF-YC1, a member of the NF-Y transcription factor family that regulates rice grain size. OsNF-YC1 knockout plants (osnf-yc1), obtained using CRISPR-Cas9 technology, showed reduced grain weight due to reduced width and thickness, with no change in grain length, leading to a slenderer grain shape. Downregulation of OsNF-YC1 using RNA interference resulted in similar grain phenotypes as osnf-yc1. OsNF-YC1 affects grain formation by regulating both cell proliferation and cell expansion. OsNF-YC1 localizes in both the nucleus and cytoplasm, has transcriptional activation activity at both the N-terminus and C-terminus, and is highly expressed in young panicles. OsNF-YC1 interacts with OsMADS1 both in vivo and in vitro. Further analysis showed that the histone-like structural CBFD-NFYB-HMF domain of OsNF-YC1 conserved in the OsNF-YC transcription factor family can directly interact with the MADS-box domain of OsMADS1 to enhance its transcriptional activation activity. This interaction positively regulates the expression of OsMADS55, the direct downstream target of OsMADS1. Therefore, this paper reveals a potential grain size regulation pathway controlled by an OsNF-YC1-OsMADS1-OsMADS55 module in rice.

ZmNF-YA1 Contributes to Maize Thermotolerance by Regulating Heat Shock Response.

Zea mays (maize) is a staple food, feed, and industrial crop. Heat stress is one of the major stresses affecting maize production and is usually accompanied by other stresses, such as drought. Our previous study identified a heterotrimer complex, ZmNF-YA1-YB16-YC17, in maize. ZmNF-YA1 and ZmNF-YB16 were positive regulators of the drought stress response and were involved in maize root development. In this study, we investigated whether ZmNF-YA1 confers heat stress tolerance in maize. The nf-ya1 mutant and overexpression lines were used to test the role of ZmNF-YA1 in maize thermotolerance. The nf-ya1 mutant was more temperature-sensitive than the wild-type (WT), while the ZmNF-YA1 overexpression lines showed a thermotolerant phenotype. Higher malondialdehyde (MDA) content and reactive oxygen species (ROS) accumulation were observed in the mutant, followed by WT and overexpression lines after heat stress treatment, while an opposite trend was observed for chlorophyll content. RNA-seq was used to analyze transcriptome changes in nf-ya1 and its wild-type control W22 in response to heat stress. Based on their expression profiles, the heat stress response-related differentially expressed genes (DEGs) in nf-ya1 compared to WT were grouped into seven clusters via k-means clustering. Gene Ontology (GO) enrichment analysis of the DEGs in different clades was performed to elucidate the roles of ZmNF-YA1-mediated transcriptional regulation and their contribution to maize thermotolerance. The loss function of ZmNF-YA1 led to the failure induction of DEGs in GO terms of protein refolding, protein stabilization, and GO terms for various stress responses. Thus, the contribution of ZmNF-YA1 to protein stabilization, refolding, and regulation of abscisic acid (ABA), ROS, and heat/temperature signaling may be the major reason why ZmNF-YA1 overexpression enhanced heat tolerance, and the mutant showed a heat-sensitive phenotype.

Identification and expression analysis of nuclear factor Y transcription factor genes under drought, cold and Eldana infestation in sugarcane (Saccharum spp. hybrid).

BACKGROUND: The Nuclear Factor Y (NF-Y) transcription factor (TF) gene family plays a crucial role in plant development and response to stress. Limited information is available on this gene family in sugarcane. OBJECTIVES: To identify sugarcane NF-Y genes through bioinformatic analysis and phylogenetic association and investigate the expression of these genes in response to abiotic and biotic stress. METHODS: Sugarcane NF-Y genes were identified using comparative genomics from functionally annotated Poaceae and Arabidopsis species. Quantitative PCR and transcriptome analysis assigned preliminary functional roles to these genes in response to water deficit, cold and African sugarcane borer (Eldana saccharina) infestation. RESULTS: We identify 21 NF-Y genes in sugarcane. Phylogenetic analysis revealed three main branches representing the subunits with potential discrepancies present in the assignment of numerical names of some NF-Y putative orthologs across the different species. Gene expression analysis indicated that three genes, ShNF-YA1, A3 and B3 were upregulated and two genes, NF-YA4 and A7 were downregulated, while three genes were upregulated, ShNF-YB2, B3 and C4, in the plants exposed to water deficit and cold stress, respectively. Functional involvement of NF-Y genes in the biotic stress response were also detected where three genes, ShNF-YA6, A3 and A7 were downregulated in the early resistant (cv. N33) response to Eldana infestation whilst only ShNF-YA6 was downregulated in the susceptible (cv. N11) early response. CONCLUSIONS: Our research findings establish a foundation for investigating the function of ShNF-Ys and offer candidate genes for stress-resistant breeding and improvement in sugarcane.

GmNF-YC4 delays soybean flowering and maturation by directly repressing GmFT2a and GmFT5a expression.

Flowering time and growth period are key agronomic traits which directly affect soybean (Glycine max (L.) Merr.) adaptation to diverse latitudes and farming systems. The FLOWERING LOCUS T (FT) homologs GmFT2a and GmFT5a integrate multiple flowering regulation pathways and significantly advance flowering and maturity in soybean. Pinpointing the genes responsible for regulating GmFT2a and GmFT5a will improve our understanding of the molecular mechanisms governing growth period in soybean. In this study, we identified the Nuclear Factor Y-C (NFY-C) protein GmNF-YC4 as a novel flowering suppressor in soybean under long-day (LD) conditions. GmNF-YC4 delays flowering and maturation by directly repressing the expression of GmFT2a and GmFT5a. In addition, we found that a strong selective sweep event occurred in the chromosomal region harboring the GmNF-YC4 gene during soybean domestication. The GmNF-YC4Hap3 allele was mainly found in wild soybean (Glycine soja Siebold & Zucc.) and has been eliminated from G. max landraces and improved cultivars, which predominantly contain the GmNF-YC4Hap1 allele. Furthermore, the Gmnf-yc4 mutants displayed notably accelerated flowering and maturation under LD conditions. These alleles may prove to be valuable genetic resources for enhancing soybean adaptability to higher latitudes.

ABA-mediated regulation of rice grain quality and seed dormancy via the NF-YB1-SLRL2-bHLH144 Module.

Abscisic acid (ABA) plays a crucial role in promoting plant stress resistance and seed dormancy. However, how ABA regulates rice quality remains unclear. This study identifies a key transcription factor SLR1-like2 (SLRL2), which mediates the ABA-regulated amylose content (AC) of rice. Mechanistically, SLRL2 interacts with NF-YB1 to co-regulate Wx, a determinant of AC and rice quality. In contrast to SLR1, SLRL2 is ABA inducible but insensitive to GA. In addition, SLRL2 exhibits DNA-binding activity and directly regulates the expression of Wx, bHLH144 and MFT2. SLRL2 competes with NF-YC12 for interaction with NF-YB1. NF-YB1 also directly represses SLRL2 transcription. Genetic validation supports that SLRL2 functions downstream of NF-YB1 and bHLH144 in regulating rice AC. Thus, an NF-YB1-SLRL2-bHLH144 regulatory module is successfully revealed. Furthermore, SLRL2 regulates rice dormancy by modulating the expression of MFT2. In conclusion, this study revealed an ABA-responsive regulatory cascade that functions in both rice quality and seed dormancy.

Expression profiling of Nuclear Factor-Y (NF-Y) transcription factors during dehydration and salt stress in finger millet reveals potential candidate genes for multiple stress tolerance.

MAIN CONCLUSION: Expression profiling of NF-Y transcription factors during dehydration and salt stress in finger millet genotypes contrastingly differing in tolerance levels identifies candidate genes for further characterization and functional studies. The Nuclear Factor-Y (NF-Y) transcription factors are known for imparting abiotic stress tolerance in different plant species. However, there is no information on the role of this transcription factor family in naturally drought-tolerant crop finger millet (Eleusine coracana L.). Therefore, interpretation of expression profiles against drought and salinity stress may provide valuable insights into specific and/or overlapping expression patterns of Eleusine coracana Nuclear Factor-Y (EcNF-Y) genes. Given this, we identified 59 NF-Y (18 NF-YA, 23 NF-YB, and 18 NF-YC) encoding genes and designated them EcNF-Y genes. Expression profiling of these genes was performed in two finger millet genotypes, PES400 (dehydration and salt stress tolerant) and VR708 (dehydration and salt stress sensitive), subjected to PEG-induced dehydration and salt (NaCl) stresses at different time intervals (0, 6, and 12 h). The qRT-PCR expression analysis reveals that the six EcNF-Y genes namely EcNF-YA1, EcNF-YA5, EcNF-YA16, EcNF-YB6, EcNF-YB10, and EcNF-YC2 might be associated with tolerance to both dehydration and salinity stress in early stress condition (6 h), suggesting the involvement of these genes in multiple stress responses in tolerant genotype. In contrast, the transcript abundance of finger millet EcNF-YA5 genes was also observed in the sensitive genotype VR708 under late stress conditions (12 h) of both dehydration and salinity stress. Therefore, the EcNF-YA5 gene might be important for adaptation to salinity and dehydration stress in sensitive finger millet genotypes. Therefore, this gene could be considered as a susceptibility determinant, which can be edited to impart tolerance. The phylogenetic analyses revealed that finger millet NF-Y genes share strong evolutionary and functional relationship to NF-Ys governing response to abiotic stresses in rice, sorghum, maize, and wheat. This is the first report of expression profiling of EcNF-Ys genes identified from the finger millet genome and reveals potential candidate for enhancing dehydration and salt tolerance.

IbNF-YA1 is a key factor in the storage root development of sweet potato.

As a major worldwide root crop, the mechanism underlying storage root yield formation has always been a hot topic in sweet potato [Ipomoea batatas (L.) Lam.]. Previously, we conducted the transcriptome database of differentially expressed genes between the cultivated sweet potato cultivar "Xushu18," its diploid wild relative Ipomoea triloba without storage root, and their interspecific somatic hybrid XT1 with medium-sized storage root. We selected one of these candidate genes, IbNF-YA1, for subsequent analysis. IbNF-YA1 encodes a nuclear transcription factor Y subunit alpha (NF-YA) gene, which is significantly induced by the natural auxin indole-3-acetic acid (IAA). The storage root yield of the IbNF-YA1 overexpression (OE) plant decreased by 29.15-40.22% compared with the wild type, while that of the RNAi plant increased by 10.16-21.58%. Additionally, IAA content increased significantly in OE plants. Conversely, the content of IAA decreased significantly in RNAi plants. Furthermore, real-time quantitative reverse transcription-PCR (qRT-PCR) analysis demonstrated that the expressions of the key genes IbYUCCA2, IbYUCCA4, and IbYUCCA8 in the IAA biosynthetic pathway were significantly changed in transgenic plants. The results indicated that IbNF-YA1 could directly target IbYUCCA4 and activate IbYUCCA4 transcription. The IAA content of IbYUCCA4 OE plants increased by 71.77-98.31%. Correspondingly, the storage root yield of the IbYUCCA4 OE plant decreased by 77.91-80.52%. These findings indicate that downregulating the IbNF-YA1 gene could improve the storage root yield in sweet potato.

Genome-wide identification and expression analysis of NF-Y gene family in tobacco (Nicotiana tabacum L.).

Nuclear factor Y (NF-Y) gene family is an important transcription factor composed of three subfamilies of NF-YA, NF-YB and NF-YC, which is involved in plant growth, development and stress response. In this study, 63 tobacco NF-Y genes (NtNF-Ys) were identified in Nicotiana tabacum L., including 17 NtNF-YAs, 30 NtNF-YBs and 16 NtNF-YCs. Phylogenetic analysis revealed ten pairs of orthologues from tomato and tobacco and 25 pairs of paralogues from tobacco. The gene structure of NtNF-YAs exhibited similarities, whereas the gene structure of NtNF-YBs and NtNF-YCs displayed significant differences. The NtNF-Ys of the same subfamily exhibited a consistent distribution of motifs and protein 3D structure. The protein interaction network revealed that NtNF-YC12 and NtNF-YC5 exhibited the highest connectivity. Many cis-acting elements related to light, stress and hormone response were found in the promoter of NtNF-Ys. Transcriptome analysis showed that more than half of the NtNF-Y genes were expressed in all tissues, and NtNF-YB9/B14/B15/B16/B17/B29 were specifically expressed in roots. A total of 15, 12, 5, and 6 NtNF-Y genes were found to respond to cold, drought, salt, and alkali stresses, respectively. The results of this study will lay a foundation for further study of NF-Y genes in tobacco and other Solanaceae plants.

Genome-Wide Identification and Drought Stress Response Pattern of the NF-Y Gene Family in Cymbidium sinense.

Cymbidium sinense, a type of orchid plant, is more drought-resistant and ornamental than other terrestrial orchids. Research has shown that many members of the NUCLEAR FACTOR Y (NF-Y) transcription factor family are responsive to plant growth, development, and abiotic stress. However, the mechanism of the NF-Y gene family's response to abiotic stress in orchids has not yet been reported. In this study, phylogenetic analysis allowed for 27 CsNF-Y genes to be identified (5 CsNF-YAs, 9 CsNF-YBs, and 13 CsNF-YC subunits), and the CsNF-Ys were homologous to those in Arabidopsis and Oryza. Protein structure analysis revealed that different subfamilies contained different motifs, but all of them contained Motif 2. Secondary and tertiary protein structure analysis indicated that the CsNF-YB and CsNF-YC subfamilies had a high content of alpha helix structures. Cis-element analysis showed that elements related to drought stress were mainly concentrated in the CsNF-YB and CsNF-YC subfamilies, with CsNF-YB3 and CsNF-YC12 having the highest content. The results of a transcriptome analysis showed that there was a trend of downregulation of almost all CsNF-Ys in leaves under drought stress, while in roots, most members of the CsNF-YB subfamily showed a trend of upregulation. Additionally, seven genes were selected for real-time reverse transcription quantitative PCR (qRT-PCR) experiments. The results were generally consistent with those of the transcriptome analysis. The regulatory roles of CsNF-YB 1, 2, and 4 were particularly evident in the roots. The findings of our study may make a great contribution to the understanding of the role of CsNF-Ys in stress-related metabolic processes.

The pancancer overexpressed NFYC Antisense 1 controls cell cycle mitotic progression through in cis and in trans modes of action.

Antisense RNAs (asRNAs) represent an underappreciated yet crucial layer of gene expression regulation. Generally thought to modulate their sense genes in cis through sequence complementarity or their act of transcription, asRNAs can also regulate different molecular targets in trans, in the nucleus or in the cytoplasm. Here, we performed an in-depth molecular characterization of NFYC Antisense 1 (NFYC-AS1), the asRNA transcribed head-to-head to NFYC subunit of the proliferation-associated NF-Y transcription factor. Our results show that NFYC-AS1 is a prevalently nuclear asRNA peaking early in the cell cycle. Comparative genomics suggests a narrow phylogenetic distribution, with a probable origin in the common ancestor of mammalian lineages. NFYC-AS1 is overexpressed pancancer, preferentially in association with RB1 mutations. Knockdown of NFYC-AS1 by antisense oligonucleotides impairs cell growth in lung squamous cell carcinoma and small cell lung cancer cells, a phenotype recapitulated by CRISPR/Cas9-deletion of its transcription start site. Surprisingly, expression of the sense gene is affected only when endogenous transcription of NFYC-AS1 is manipulated. This suggests that regulation of cell proliferation is at least in part independent of the in cis transcription-mediated effect on NFYC and is possibly exerted by RNA-dependent in trans effects converging on the regulation of G2/M cell cycle phase genes. Accordingly, NFYC-AS1-depleted cells are stuck in mitosis, indicating defects in mitotic progression. Overall, NFYC-AS1 emerged as a cell cycle-regulating asRNA with dual action, holding therapeutic potential in different cancer types, including the very aggressive RB1-mutated tumors.

Two different viral proteins suppress NUCLEAR FACTOR-YC-mediated antiviral immunity during infection in rice.

Plant viruses have multiple strategies to counter and evade the host's antiviral immune response. However, limited research has been conducted on the antiviral defense mechanisms commonly targeted by distinct types of plant viruses. In this study, we discovered that NUCLEAR FACTOR-YC (NF-YC) and NUCLEAR FACTOR-YA (NF-YA), 2 essential components of the NF-Y complex, were commonly targeted by viral proteins encoded by 2 different rice (Oryza sativa L.) viruses, rice stripe virus (RSV, Tenuivirus) and southern rice black streaked dwarf virus (SRBSDV, Fijivirus). In vitro and in vivo experiments showed that OsNF-YCs associate with OsNF-YAs and inhibit their transcriptional activation activity, resulting in the suppression of OsNF-YA-mediated plant susceptibility to rice viruses. Different viral proteins RSV P2 and SRBSDV SP8 directly disrupted the association of OsNF-YCs with OsNF-YAs, thereby suppressing the antiviral defense mediated by OsNF-YCs. These findings suggest an approach for conferring broad-spectrum disease resistance in rice and reveal a common mechanism employed by viral proteins to evade the host's antiviral defense by hindering the antiviral capabilities of OsNF-YCs.

Jasmonate signaling pathway confers salt tolerance through a NUCLEAR FACTOR-Y trimeric transcription factor complex in Arabidopsis.

Jasmonate (JA) is a well-known phytohormone essential for plant response to biotic stress. Recently, a crucial role of JA signaling in salt resistance has been highlighted; however, the specific regulatory mechanism remains largely unknown. In this study, we found that the NUCLEAR FACTOR-Y (NF-Y) subunits NF-YA1, NF-YB2, and NF-YC9 form a trimeric complex that positively regulates the expression of salinity-responsive genes, whereas JASMONATE-ZIM DOMAIN protein 8 (JAZ8) directly interacts with three subunits and acts as the key repressor to suppress both the assembly of the NF-YA1-YB2-YC9 trimeric complex and the transcriptional activation activity of the complex. When plants encounter high salinity, JA levels are elevated and perceived by the CORONATINE INSENSITIVE (COI) 1 receptor, leading to the degradation of JAZ8 via the 26S proteasome pathway, thereby releasing the activity of the NF-YA1-YB2-YC9 complex, initiating the activation of salinity-responsive genes, such as MYB75, and thus enhancing the salinity tolerance of plants.

Expression and function of NF-Y subunits in cancer.

NF-Y is a Transcription Factor (TF) targeting the CCAAT box regulatory element. It consists of the NF-YB/NF-YC heterodimer, each containing an Histone Fold Domain (HFD), and the sequence-specific subunit NF-YA. NF-YA expression is associated with cell proliferation and absent in some post-mitotic cells. The review summarizes recent findings impacting on cancer development. The logic of the NF-Y regulome points to pro-growth, oncogenic genes in the cell-cycle, metabolism and transcriptional regulation routes. NF-YA is involved in growth/differentiation decisions upon cell-cycle re-entry after mitosis and it is widely overexpressed in tumors, the HFD subunits in some tumor types or subtypes. Overexpression of NF-Y -mostly NF-YA- is oncogenic and decreases sensitivity to anti-neoplastic drugs. The specific roles of NF-YA and NF-YC isoforms generated by alternative splicing -AS- are discussed, including the prognostic value of their levels, although the specific molecular mechanisms of activity are still to be deciphered.

The transcription factor NF-YA is crucial for neural progenitor maintenance during brain development.

In contrast to stage-specific transcription factors, the role of ubiquitous transcription factors in neuronal development remains a matter of scrutiny. Here, we demonstrated that a ubiquitous factor NF-Y is essential for neural progenitor maintenance during brain morphogenesis. Deletion of the NF-YA subunit in neural progenitors by using nestin-cre transgene in mice resulted in significant abnormalities in brain morphology, including a thinner cerebral cortex and loss of striatum during embryogenesis. Detailed analyses revealed a progressive decline in multiple neural progenitors in the cerebral cortex and ganglionic eminences, accompanied by induced apoptotic cell death and reduced cell proliferation. In neural progenitors, the NF-YA short isoform lacking exon 3 is dominant and co-expressed with cell cycle genes. ChIP-seq analysis from the cortex during early corticogenesis revealed preferential binding of NF-Y to the cell cycle genes, some of which were confirmed to be downregulated following NF-YA deletion. Notably, the NF-YA short isoform disappears and is replaced by its long isoform during neuronal differentiation. Forced expression of the NF-YA long isoform in neural progenitors resulted in a significant decline in neuronal count, possibly due to the suppression of cell proliferation. Collectively, we elucidated a critical role of the NF-YA short isoform in maintaining neural progenitors, possibly by regulating cell proliferation and apoptosis. Moreover, we identified an isoform switch in NF-YA within the neuronal lineage in vivo, which may explain the stage-specific role of NF-Y during neuronal development.

Nuclear factor Y is a pervasive regulator of neuronal gene expression.

Nervous system function relies on the establishment of complex gene expression programs that provide neuron-type-specific and core pan-neuronal features. These complementary regulatory paradigms are controlled by terminal selector and parallel-acting transcription factors (TFs), respectively. Here, we identify the nuclear factor Y (NF-Y) TF as a pervasive direct and indirect regulator of both neuron-type-specific and pan-neuronal gene expression. Mapping global NF-Y targets reveals direct binding to the cis-regulatory regions of pan-neuronal genes and terminal selector TFs. We show that NFYA-1 controls pan-neuronal gene expression directly through binding to CCAAT boxes in target gene promoters and indirectly by regulating the expression of terminal selector TFs. Further, we find that NFYA-1 regulation of neuronal gene expression is important for neuronal activity and motor function. Thus, our research sheds light on how global neuronal gene expression programs are buffered through direct and indirect regulatory mechanisms.

Characterization of NF-Y gene family and their expression and interaction analysis in Phalaenopsis orchid.

The complex of Nuclear Factor Ys (NF-Ys), a family of heterotrimeric transcription factors composed of three unique subunits (NF-YA, NF-YB, and NF-YC), binds to the CCAAT box of eukaryotic promoters to activate or repress transcription of the downstream genes involved into various biological processes in plants. However, the systematic characterization of NF-Y gene family has not been elucidated in Phalaenopsis. A total of 24 NF-Y subunits (4 NF-YA, 9 NF-YB, and 11 NF-YC subunits) were identified in Phalaenopsis genome, whose exon/intron structures were highly differentiated among the PhNF-Y subunits. The distribution of motifs between coding regions of PhNF-YA and PhNF-YB/C was distinct. Segmental and tandem duplication events among paralogous PhNF-Ys were occurred. Six pairs of orthologous NF-Ys from Phalaenopsis and Arabidopsis and five pairs of orthologous NF-Ys from Phalaenopsis and rice involved in the phylogenetic gene synteny were identified. The various cis-elements being responsive to low-temperature, drought and ABA were distributed in the promoters of PhNF-Ys. qRT-PCR analysis indicated all of PhNF-Ys displayed the spatial specificity of expression in different tissues. Moreover, the expression levels of multiple PhNF-Ys significantly changed responding to low-temperature and ABA treatment. Yeast two hybrid and bimolecular fluorescence complementation assays approved the interaction of PhNF-YA1/3 with PhNF-YB6/PhNF-YC7, respectively, as well as PhNF-YB6 with PhNF-YC7. PhNF-YA1/3, PhNF-YB6, and PhNF-YC7 proteins were all localized in the nucleus. Further, transient overexpression of PhNF-YB6 and PhNF-YC7 promoted PhFT3 and repressed PhSVP expression in Phalaenopsis. These findings will facilitate to explore the role of PhNF-Ys in floral transition in Phalaenopsis orchid.

Analysis of gene duplication within the Arabidopsis NUCLEAR FACTOR Y, subunit B (NF-YB) protein family reveals domains under both purifying and diversifying selection.

Gene duplication is an evolutionary mechanism that provides new genetic material. Since gene duplication is a major driver for molecular evolution, examining the fate of duplicated genes is an area of active research. The fate of duplicated genes can include loss, subfunctionalization, and neofunctionalization. In this manuscript, we chose to experimentally study the fate of duplicated genes using the Arabidopsis NUCLEAR FACTOR Y (NF-Y) transcription factor family. NF-Y transcription factors are heterotrimeric complexes, composed of NF-YA, NF-YB, and NF-YC. NF-YA subunits are responsible for nucleotide-specific binding to a CCAAT cis-regulatory element. NF-YB and NF-YC subunits make less specific, but essential complex-stabilizing contacts with the DNA flanking the core CCAAT pentamer. While ubiquitous in eukaryotes, each NF-Y family has expanded by duplication in the plant lineage. For example, the model plant Arabidopsis contains 10 each of the NF-Y subunits. Here we examine the fate of duplicated NF-YB proteins in Arabidopsis, which are composed of central histone fold domains (HFD) and less conserved flanking regions (N- and C-termini). Specifically, the principal question we wished to address in this manuscript was to what extent can the 10 Arabidopsis NF-YB paralogs functionally substitute the genes NF-YB2 and NF-YB3 in the promotion of photoperiodic flowering? Our results demonstrate that the conserved histone fold domains (HFD) may be under pressure for purifying (negative) selection, while the non-conserved N- and C-termini may be under pressure for diversifying (positive) selection, which explained each paralog's ability to substitute. In conclusion, our data demonstrate that the N- and C-termini may have allowed the duplicated genes to undergo functional diversification, allowing the retention of the duplicated genes.