Sequence-specific transcription factor NF-Y displays histone-like DNA binding and H2B-like ubiquitination.

The sequence-specific transcription factor NF-Y binds the CCAAT box, one of the sequence elements most frequently found in eukaryotic promoters. NF-Y is composed of the NF-YA and NF-YB/NF-YC subunits, the latter two hosting histone-fold domains (HFDs). The crystal structure of NF-Y bound to a 25 bp CCAAT oligonucleotide shows that the HFD dimer binds to the DNA sugar-phosphate backbone, mimicking the nucleosome H2A/H2B-DNA assembly. NF-YA both binds to NF-YB/NF-YC and inserts an α helix deeply into the DNA minor groove, providing sequence-specific contacts to the CCAAT box. Structural considerations and mutational data indicate that NF-YB ubiquitination at Lys138 precedes and is equivalent to H2B Lys120 monoubiquitination, important in transcriptional activation. Thus, NF-Y is a sequence-specific transcription factor with nucleosome-like properties of nonspecific DNA binding and helps establish permissive chromatin modifications at CCAAT promoters. Our findings suggest that other HFD-containing proteins may function in similar ways.

Myo-differentiation reporter screen reveals NF-Y as an activator of PAX3-FOXO1 in rhabdomyosarcoma.

Recurrent chromosomal rearrangements found in rhabdomyosarcoma (RMS) produce the PAX3-FOXO1 fusion protein, which is an oncogenic driver and a dependency in this disease. One important function of PAX3-FOXO1 is to arrest myogenic differentiation, which is linked to the ability of RMS cells to gain an unlimited proliferation potential. Here, we developed a phenotypic screening strategy for identifying factors that collaborate with PAX3-FOXO1 to block myo-differentiation in RMS. Unlike most genes evaluated in our screen, we found that loss of any of the three subunits of the Nuclear Factor Y (NF-Y) complex leads to a myo-differentiation phenotype that resembles the effect of inactivating PAX3-FOXO1. While the transcriptomes of NF-Y- and PAX3-FOXO1-deficient RMS cells bear remarkable similarity to one another, we found that these two transcription factors occupy nonoverlapping sites along the genome: NF-Y preferentially occupies promoters, whereas PAX3-FOXO1 primarily binds to distal enhancers. By integrating multiple functional approaches, we map the PAX3 promoter as the point of intersection between these two regulators. We show that NF-Y occupies CCAAT motifs present upstream of PAX3 to function as a transcriptional activator of PAX3-FOXO1 expression in RMS. These findings reveal a critical upstream role of NF-Y in the oncogenic PAX3-FOXO1 pathway, highlighting how a broadly essential transcription factor can perform tumor-specific roles in governing cellular state.

Genomic binding of NF-Y in mouse and human cells.

NF-Y is a Transcription Factor that regulates transcription through binding to the CCAAT-box. To understand its strategy, we analyzed 16 ChIP-seq datasets from human and mouse cells. Shared loci, mostly located in promoters of expressed genes of cell cycle, metabolism and gene expression pathways, are associated with histone marks of active chromatin and specific modules of TFs. Other peaks are in enhancers and Transposable Elements -TE- of retroviral origin in human and mouse. We evaluated the relationship with USF1, a common synergistic partner in promoters and MLT1 TEs, upon NF-YB inactivation: USF1 binding decreases in promoters, modestly in MLT1, suggesting a pioneering role of NF-Y in formers, not in the latters. These data define a common set of NF-Y functional targets across different mammalian cell types, suggesting a pioneering role in promoters with respect to TEs.

Genetic legacy and adaptive signatures: investigating the history, diversity, and selection signatures in Rendena cattle resilient to eighteenth century rinderpest epidemics.

BACKGROUND: Rendena is a dual-purpose cattle breed, which is primarily found in the Italian Alps and the eastern areas of the Po valley, and recognized for its longevity, fertility, disease resistance and adaptability to steep Alpine pastures. It is categorized as 'vulnerable to extinction' with only 6057 registered animals in 2022, yet no comprehensive analyses of its molecular diversity have been performed to date. The aim of this study was to analyse the origin, genetic diversity, and genomic signatures of selection in Rendena cattle using data from samples collected in 2000 and 2018, and shed light on the breed's evolution and conservation needs. RESULTS: Genetic analysis revealed that the Rendena breed shares genetic components with various Alpine and Po valley breeds, with a marked genetic proximity to the Original Braunvieh breed, reflecting historical restocking efforts across the region. The breed shows signatures of selection related to both milk and meat production, environmental adaptation and immune response, the latter being possibly the result of multiple rinderpest epidemics that swept across the Alps in the eighteenth century. An analysis of the Rendena cattle population spanning 18 years showed an increase in the mean level of inbreeding over time, which is confirmed by the mean number of runs of homozygosity per individual, which was larger in the 2018 sample. CONCLUSIONS: The Rendena breed, while sharing a common origin with Brown Swiss, has developed distinct traits that enable it to thrive in the Alpine environment and make it highly valued by local farmers. Preserving these adaptive features is essential, not only for maintaining genetic diversity and enhancing the ability of this traditional animal husbandry to adapt to changing environments, but also for guaranteeing the resilience and sustainability of both this livestock system and the livelihoods within the Rendena valley.

Long-Term SARS-CoV-2 Antibody Seroprevalence in Blood Donors, Italy.

We evaluated SARS-CoV-2 antibody response in voluntary blood donors in Italy at different timepoints. Immediately after lockdown easing, 908/25,657 donors (3.5%) had low IgG titers against nucleocapsid. In the next 2 years, titers increased despite few COVID-19 symptoms. On multivariate analysis, allergic rhinitis was associated with reduced risk for symptomatic COVID-19.

Genetic correlations of direct and indirect genetic components of social dominance with fitness and morphology traits in cattle.

BACKGROUND: Within the same species, individuals show marked variation in their social dominance. Studies on a handful of populations have indicated heritable genetic variation for this trait, which is determined by both the genetic background of the individual (direct genetic effect) and of its opponent (indirect genetic effect). However, the evolutionary consequences of selection for this trait are largely speculative, as it is not a usual target of selection in livestock populations. Moreover, studying social dominance presents the challenge of working with a phenotype with a mean value that cannot change in the population, as for every winner of an agonistic interaction there will necessarily be a loser. Thus, to investigate what could be the evolutionary response to selection for social dominance, it is necessary to focus on traits that might be correlated with it. This study investigated the genetic correlations of social dominance, both direct and indirect, with several morphology and fitness traits. We used a dataset of agonistic contests involving cattle (Bos taurus): during these contests, pairs of cows compete in ritualized interactions to assess social dominance. The outcomes of 37,996 dominance interactions performed by 8789 cows over 20 years were combined with individual data for fertility, mammary health, milk yield and morphology and analysed using bivariate animal models including indirect genetic effects. RESULTS: We found that winning agonistic interactions has a positive genetic correlation with more developed frontal muscle mass, lower fertility, and poorer udder health. We also discovered that the trends of changes in the estimated breeding values of social dominance, udder health and more developed muscle mass were consistent with selection for social dominance in the population. CONCLUSIONS: We present evidence that social dominance is genetically correlated with fitness traits, as well as empirical evidence of the possible evolutionary trade-offs between these traits. We show that it is feasible to estimate genetic correlations involving dyadic social traits.

Phylogeny of NF-YA trans-activation splicing isoforms in vertebrate evolution.

NF-Y is a trimeric pioneer Transcription Factor (TF) whose target sequence -the CCAAT box- is present in ~25% of mammalian promoters. We reconstruct the phylogenetic history of the regulatory NF-YA subunit in vertebrates. We find that in addition to the remarkable conservation of the subunits-interaction and DNA-binding parts, the Transcriptional Activation Domain (TAD) is also conserved (>90% identity among bony vertebrates). We infer the phylogeny of the alternatively spliced exon-3 and partial splicing events of exon-7 -7N and 7C- revealing independent clade-specific losses of these regions. These isoforms shape the TAD. Absence of exon-3 in basal deuterostomes, cartilaginous fishes and hagfish, but not in lampreys, suggests that the "short" isoform is primordial, with emergence of exon-3 in chordates. Exon 7N was present in the vertebrate common ancestor, while 7C is a molecular innovation of teleost fishes. RNA-seq analysis in several species confirms expression of all these isoforms. We identify 3 blocks of amino acids in the TAD shared across deuterostomes, yet structural predictions and sequence analyses suggest an evolutionary drive for maintenance of an Intrinsically Disordered Region -IDR- within the TAD. Overall, these data help reconstruct the logic for alternative splicing of this essential eukaryotic TF.

Structural determinants for NF-Y subunit organization and NF-Y/DNA association in plants.

NF-Y transcription factor comprises three subunits: NF-YA, NF-YB and NF-YC. NF-YB and NF-YC dimerize through their histone fold domain (HFD), which can bind DNA in a non-sequence-specific fashion while serving as a scaffold for NF-YA trimerization. Upon trimerization, NF-YA specifically recognizes the CCAAT box sequence on promoters and enhancers. In plants, each NF-Y subunit is encoded by several genes giving rise to hundreds of potential heterotrimeric combinations. In addition, plant NF-YBs and NF-YCs interact with other protein partners to recognize a plethora of genomic motifs, as the CCT protein family that binds CORE sites. The NF-Y subunit organization and its DNA-binding properties, together with the NF-Y HFD capacity to adapt different protein modules, represent plant-specific features that play a key role in development, growth and reproduction. Despite their relevance, these features are still poorly understood at the molecular level. Here, we present the structures of Arabidopsis and rice NF-YB/NF-YC dimers, and of an Arabidopsis NF-Y trimer in complex with the FT CCAAT box, together with biochemical data on NF-Y mutants. The dimeric structures identify the key residues for NF-Y HFD stabilization. The NF-Y/DNA structure and the mutation experiments shed light on HFD trimerization interface properties and the NF-YA sequence appetite for the bases flanking the CCAAT motif. These data explain the logic of plant NF-Y gene expansion: the trimerization adaptability and the flexible DNA-binding rules serve the scopes of accommodating the large number of NF-YAs, CCTs and possibly other NF-Y HFD binding partners and a diverse audience of genomic motifs.

Comparative analysis of inbreeding parameters and runs of homozygosity islands in 2 Italian autochthonous cattle breeds mainly raised in the Parmigiano-Reggiano cheese production region.

Reggiana and Modenese are autochthonous cattle breeds, reared in the North of Italy, that can be mainly distinguished for their standard coat color (Reggiana is red, whereas Modenese is white with some pale gray shades). Almost all milk produced by these breeds is transformed into 2 mono-breed branded Parmigiano-Reggiano cheeses, from which farmers receive the economic incomes needed for the sustainable conservation of these animal genetic resources. After the setting up of their herd books in 1960s, these breeds experienced a strong reduction in the population size that was subsequently reverted starting in the 1990s (Reggiana) or more recently (Modenese) reaching at present a total of about 2,800 and 500 registered cows, respectively. Due to the small population size of these breeds, inbreeding is a very important cause of concern for their conservation programs. Inbreeding is traditionally estimated using pedigree data, which are summarized in an inbreeding coefficient calculated at the individual level (FPED). However, incompleteness of pedigree information and registration errors can affect the effectiveness of conservation strategies. High-throughput SNP genotyping platforms allow investigation of inbreeding using genome information that can overcome the limits of pedigree data. Several approaches have been proposed to estimate genomic inbreeding, with the use of runs of homozygosity (ROH) considered to be the more appropriate. In this study, several pedigree and genomic inbreeding parameters, calculated using the whole herd book populations or considering genotyping information (GeneSeek GGP Bovine 150K) from 1,684 Reggiana cattle and 323 Modenese cattle, were compared. Average inbreeding values per year were used to calculate effective population size. Reggiana breed had generally lower genomic inbreeding values than Modenese breed. The low correlation between pedigree-based and genomic-based parameters (ranging from 0.187 to 0.195 and 0.319 to 0.323 in the Reggiana and Modenese breeds, respectively) reflected the common problems of local populations in which pedigree records are not complete. The high proportion of short ROH over the total number of ROH indicates no major recent inbreeding events in both breeds. ROH islands spread over the genome of the 2 breeds (15 in Reggiana and 14 in Modenese) identified several signatures of selection. Some of these included genes affecting milk production traits, stature, body conformation traits (with a main ROH island in both breeds on BTA6 containing the ABCG2, NCAPG, and LCORL genes) and coat color (on BTA13 in Modenese containing the ASIP gene). In conclusion, this work provides an extensive comparative analysis of pedigree and genomic inbreeding parameters and relevant genomic information that will be useful in the conservation strategies of these 2 iconic local cattle breeds.

On the NF-Y regulome as in ENCODE (2019).

NF-Y is a trimeric Transcription Factor -TF- which binds with high selectivity to the conserved CCAAT element. Individual ChIP-seq analysis as well as ENCODE have progressively identified locations shared by other TFs. Here, we have analyzed data introduced by ENCODE over the last five years in K562, HeLa-S3 and GM12878, including several chromatin features, as well RNA-seq profiling of HeLa cells after NF-Y inactivation. We double the number of sequence-specific TFs and co-factors reported. We catalogue them in 4 classes based on co-association criteria, infer target genes categorizations, identify positional bias of binding sites and gene expression changes. Larger and novel co-associations emerge, specifically concerning subunits of repressive complexes as well as RNA-binding proteins. On the one hand, these data better define NF-Y association with single members of major classes of TFs, on the other, they suggest that it might have a wider role in the control of mRNA production.

CONSTANS Imparts DNA Sequence Specificity to the Histone Fold NF-YB/NF-YC Dimer.

Nuclear Factor Y (NF-Y) is a heterotrimeric transcription factor that binds CCAAT elements. The NF-Y trimer is composed of a Histone Fold Domain (HFD) dimer (NF-YB/NF-YC) and NF-YA, which confers DNA sequence specificity. NF-YA shares a conserved domain with the CONSTANS, CONSTANS-LIKE, TOC1 (CCT) proteins. We show that CONSTANS (CO/B-BOX PROTEIN1 BBX1), a master flowering regulator, forms a trimer with Arabidopsis thaliana NF-YB2/NF-YC3 to efficiently bind the CORE element of the FLOWERING LOCUS T promoter. We term this complex NF-CO. Using saturation mutagenesis, electrophoretic mobility shift assays, and RNA-sequencing profiling of co, nf-yb, and nf-yc mutants, we identify CCACA elements as the core NF-CO binding site. CO physically interacts with the same HFD surface required for NF-YA association, as determined by mutations in NF-YB2 and NF-YC9, and tested in vitro and in vivo. The co-7 mutation in the CCT domain, corresponding to an NF-YA arginine directly involved in CCAAT recognition, abolishes NF-CO binding to DNA. In summary, a unifying molecular mechanism of CO function relates it to the NF-YA paradigm, as part of a trimeric complex imparting sequence specificity to HFD/DNA interactions. It is likely that members of the large CCT family participate in similar complexes with At-NF-YB and At-NF-YC, broadening HFD combinatorial possibilities in terms of trimerization, DNA binding specificities, and transcriptional regulation.

The phosphorylatable Ser320 of NF-YA is involved in DNA binding of the NF-Y trimer.

Nuclear factor Y (NF-Y) is a transcription factor trimer binding to the functionally important CCAAT box, present in promoters of growth-promoting and cell cycle-regulated genes. The regulatory nuclear factor YA (NF-YA) subunit confers sequence-specificity to the histone-like nuclear factor YB/YC dimer. NF-YA harbors 2 serines-Ser320 and Ser326-shown to be phosphorylated by cyclin-dependent kinase 2. High-throughput proteomics data indicate that they are phosphorylated in vivo. Specifically, Ser320 makes structural contacts with the DNA phosphate backbone; Ser320-P is the major NF-YA phosphorylation isoform following overexpression in HeLa cells, increasing upon mitotic arrest. EMSA with recombinant Ala and Glu mutants confirm a role of Ser320, but not Ser326, in stabilization of DNA binding. Transactivation assays of the CCAAT-dependent MDR1 and RHOB promoters show loss in transcription function for Ser320Glu and Ser320Ala NF-YA mutants. Phylogenetic analysis of NF-YA proteins indicates that Ser320 is indeed evolutionarily conserved. We conclude that phosphorylation of this residue belongs to the core mechanisms of DNA-binding control, possibly driven by the necessity to unfasten binding of or to evict NF-Y from CCAAT sites under specific conditions of growth regulation.-Bernardini, A., Lorenzo, M., Nardini, M., Mantovani, R., Gnesutta, N. The phosphorylatable Ser320 of NF-YA is involved in DNA binding of the NF-Y trimer.

The genetic heritage of Alpine local cattle breeds using genomic SNP data.

BACKGROUND: Assessment of genetic diversity and population structure provides important control metrics to avoid genetic erosion, inbreeding depression and crossbreeding between exotic and locally-adapted cattle breeds since these events can have deleterious consequences and eventually lead to extinction. Historically, the Alpine Arc represents an important pocket of cattle biodiversity with a large number of autochthonous breeds that provide a fundamental source of income for the entire regional economy. By using genotype data from medium-density single nucleotide polymorphism (SNP) arrays, we performed a genome-wide comparative study of 23 cattle populations from the Alpine Arc and three cosmopolitan breeds. RESULTS: After filtering, we obtained a final genotyping dataset consisting of 30,176 SNPs for 711 individuals. The local breeds showed high or intermediate values of genetic diversity compared to the highly selected cosmopolitan breeds. Patterns of genetic differentiation, multidimensional scaling, admixture analysis and the constructed phylogenetic tree showed convergence, which indicates the presence of gene flow among the breeds according to both geographic origin and historical background. Among the most differentiated breeds, we identified the modern Brown cattle. In spite of admixture events, several local breeds have preserved distinctive characteristics, which is probably due to differences in genetic origin and geographic location. CONCLUSIONS: This study represents one of the most comprehensive genome-wide analysis of the Alpine cattle breeds to date. Using such a large dataset that includes the majority of the local breeds found in this region, allowed us to expand knowledge on the evaluation and status of Alpine cattle biodiversity. Our results indicate that although many of the analyzed local breeds are listed as endangered, they still harbor a large amount of genetic diversity, even when compared to some cosmopolitan breeds. This finding, together with the reconstruction of the phylogeny and the relationships between these Alpine Arc cattle breeds, provide crucial insights not only into the improvement of genetic stocks but also into the implementation of future conservation strategies.

Transcriptional and Post-transcriptional Mechanisms Limit Heading Date 1 (Hd1) Function to Adapt Rice to High Latitudes.

Rice flowering is controlled by changes in the photoperiod that promote the transition to the reproductive phase as days become shorter. Natural genetic variation for flowering time has been largely documented and has been instrumental to define the genetics of the photoperiodic pathway, as well as providing valuable material for artificial selection of varieties better adapted to local environments. We mined genetic variation in a collection of rice varieties highly adapted to European regions and isolated distinct variants of the long day repressor HEADING DATE 1 (Hd1) that perturb its expression or protein function. Specific variants allowed us to define novel features of the photoperiodic flowering pathway. We demonstrate that a histone fold domain scaffold formed by GRAIN YIELD, PLANT HEIGHT AND HEADING DATE 8 (Ghd8) and several NF-YC subunits can accommodate distinct proteins, including Hd1 and PSEUDO RESPONSE REGULATOR 37 (PRR37), and that the resulting OsNF-Y complex containing Hd1 can bind a specific sequence in the promoter of HEADING DATE 3A (Hd3a). Artificial selection has locally favored an Hd1 variant unable to assemble in such heterotrimeric complex. The causal polymorphism was defined as a single conserved lysine in the CCT domain of the Hd1 protein. Our results indicate how genetic variation can be stratified and explored at multiple levels, and how its description can contribute to the molecular understanding of basic developmental processes.

NF-Y Overexpression in Liver Hepatocellular Carcinoma (HCC).

NF-Y is a pioneer trimeric transcription factor formed by the Histone Fold Domain (HFD) NF-YB/NF-YC subunits and NF-YA. Three subunits are required for DNA binding. CCAAT-specificity resides in NF-YA and transactivation resides in Q-rich domains of NF-YA and NF-YC. They are involved in alternative splicing (AS). We recently showed that NF-YA is overexpressed in breast and lung carcinomas. We report here on the overexpression of all subunits in the liver hepatocellular carcinoma (HCC) TCGA database, specifically the short NF-YAs and NF-YC2 (37 kDa) isoforms. This is observed at all tumor stages, in viral-infected samples and independently from the inflammatory status. Up-regulation of NF-YAs and NF-YC, but not NF-YB, is associated to tumors with mutant p53. We used a deep-learning-based method (DeepCC) to extend the partitioning of the three molecular clusters to all HCC TCGA tumors. In iCluster3, CCAAT is a primary matrix found in promoters of up-regulated genes, and cell-cycle pathways are enriched. Finally, clinical data indicate that, globally, only NF-YAs, but not HFD subunits, correlate with the worst prognosis; in iCluster1 patients, however, all subunits correlate. The data show a difference with other epithelial cancers, in that global overexpression of the three subunits is reported and clinically relevant in a subset of patients; yet, they further reinstate the regulatory role of the sequence-specific subunit.

NUCLEAR FACTOR Y, Subunit A (NF-YA) Proteins Positively Regulate Flowering and Act Through FLOWERING LOCUS T.

Photoperiod dependent flowering is one of several mechanisms used by plants to initiate the developmental transition from vegetative growth to reproductive growth. The NUCLEAR FACTOR Y (NF-Y) transcription factors are heterotrimeric complexes composed of NF-YA and histone-fold domain (HFD) containing NF-YB/NF-YC, that initiate photoperiod-dependent flowering by cooperatively interacting with CONSTANS (CO) to drive the expression of FLOWERING LOCUS T (FT). This involves NF-Y and CO binding at distal CCAAT and proximal "CORE" elements, respectively, in the FT promoter. While this is well established for the HFD subunits, there remains some question over the potential role of NF-YA as either positive or negative regulators of this process. Here we provide strong support, in the form of genetic and biochemical analyses, that NF-YA, in complex with NF-YB/NF-YC proteins, can directly bind the distal CCAAT box in the FT promoter and are positive regulators of flowering in an FT-dependent manner.

Conservation status and historical relatedness of Italian cattle breeds.

BACKGROUND: In the last 50 years, the diversity of cattle breeds has experienced a severe contraction. However, in spite of the growing diffusion of cosmopolite specialized breeds, several local cattle breeds are still farmed in Italy. Genetic characterization of breeds represents an essential step to guide decisions in the management of farm animal genetic resources. The aim of this work was to provide a high-resolution representation of the genome-wide diversity and population structure of Italian local cattle breeds using a medium-density single nucleotide polymorphism (SNP) array. RESULTS: After quality control filtering, the dataset included 31,013 SNPs for 800 samples from 32 breeds. Our results on the genetic diversity of these breeds agree largely with their recorded history. We observed a low level of genetic diversity, which together with the small size of the effective populations, confirmed that several breeds are threatened with extinction. According to the analysis of runs of homozygosity, evidence of recent inbreeding was strong in some local breeds, such as Garfagnina, Mucca Pisana and Pontremolese. Patterns of genetic differentiation, shared ancestry, admixture events, and the phylogenetic tree, all suggest the presence of gene flow, in particular among breeds that originate from the same geographical area, such as the Sicilian breeds. In spite of the complex admixture events that most Italian cattle breeds have experienced, they have preserved distinctive characteristics and can be clearly discriminated, which is probably due to differences in genetic origin, environment, genetic isolation and inbreeding. CONCLUSIONS: This study is the first exhaustive genome-wide analysis of the diversity of Italian cattle breeds. The results are of significant importance because they will help design and implement conservation strategies. Indeed, efforts to maintain genetic diversity in these breeds are needed. Improvement of systems to record and monitor inbreeding in these breeds may contribute to their in situ conservation and, in view of this, the availability of genomic data is a fundamental resource.

A high definition look at the NF-Y regulome reveals genome-wide associations with selected transcription factors.

NF-Y is a trimeric transcription factor (TF), binding the CCAAT box element, for which several results suggest a pioneering role in activation of transcription. In this work, we integrated 380 ENCODE ChIP-Seq experiments for 154 TFs and cofactors with sequence analysis, protein-protein interactions and RNA profiling data, in order to identify genome-wide regulatory modules resulting from the co-association of NF-Y with other TFs. We identified three main degrees of co-association with NF-Y for sequence-specific TFs. In the most relevant one, we found TFs having a significant overlap with NF-Y in their DNA binding loci, some with a precise spacing of binding sites with respect to the CCAAT box, others (FOS, Sp1/2, RFX5, IRF3, PBX3) mostly lacking their canonical binding site and bound to arrays of well spaced CCAAT boxes. As expected, NF-Y binding also correlates with RNA Pol II General TFs and with subunits of complexes involved in the control of H3K4 methylations. Co-association patterns are confirmed by protein-protein interactions, and correspond to specific functional categorizations and expression level changes of target genes following NF-Y inactivation. These data define genome-wide rules for the organization of NF-Y-centered regulatory modules, supporting a model of distinct categorization and synergy with well defined sets of TFs.

Genetic parameters of different measures of somatic cell counts in the Rendena breed.

The objective of this study was to consider different and alternative methods of using somatic cell count (SCC) data recorded according to the Italian official milk recording system, estimating its genetic parameters and the correlations with the yield traits (milk, fat, and protein) in the Rendena breed. The SCC traits defined for genetic evaluation were somatic cell score, log of the total daily SCC (LTSCC, i.e., SCC multiplied by daily milk yield) individually recorded in a day of official control, and 3 different thresholds (≥80,000, ≥150,000, and ≥400,000 cells/mL) for somatic cells. A total of 187,052 test-day monthly records of milk, fat, and protein yields and SCC belonging to 11,718 cows were used to estimate heritability and genetic correlations between SCC and yield traits via a bi-trait repeatability test-day model using a Bayesian approach. The heritability values estimated for the threshold traits ranged from 0.036 to 0.065, less than those observed for monthly somatic cell score and LTSCC traits that were equivalent to 0.088 and 0.103, respectively. Higher genetic correlations were estimated between LTSCC trait and all productive traits (0.379 for milk, 0.240 for fat, and 0.370 for protein). The other SCC traits considered have shown low or almost null genetic correlations with the productive traits (from 0.008 between fat yield and SCC ≥150,000 cells/mL to 0.234 between protein yield and SCC ≥400,000 cells/mL) and almost all estimates included zero in the 95% highest posterior density region interval. These results indicated that genetic selection for milk, fat, and protein production negatively affects the LTSCC content and SCC ≥400,000 cells/mL but does not negatively influence the other somatic cell and threshold SCC traits in the Rendena breed. However, the complete framework of genetic relationships of SCC with all traits under selection should be considered when deciding on the possible inclusion of SCC in the breeding program of this small cattle population.

NF-YA splice variants have different roles on muscle differentiation.

The heterotrimeric CCAAT-binding factor NF-Y controls the expression of a multitude of genes involved in cell cycle progression. NF-YA is present in two alternatively spliced isoforms, NF-YAs and NF-YAl, differing in 28 aminoacids in the N-terminal Q-rich activation domain. NF-YAs has been identified as a regulator of stemness and proliferation in mouse embryonic cells (mESCs) and human hematopoietic stem cells (hHSCs), whereas the role of NF-YAl is not clear. In the muscle system, NF-YA expression is observed in proliferating cells, but barely detectable in terminally differentiated cells in vitro and adult skeletal muscle in vivo. Here, we show that NF-YA inactivation in mouse myoblasts impairs both proliferation and differentiation. The overexpression of the two NF-YA isoforms differentially affects myoblasts fate: NF-YAs enhance cell proliferation, while NF-YAl boosts differentiation. The molecular mechanisms were investigated by expression profilings, detailing the opposite programs of the two isoforms. Bioinformatic analysis of the regulated promoters failed to detect a significant presence of CCAAT boxes in the regulated genes. NF-YAl activates directly Mef2D, Six genes, and p57kip2 (Cdkn1c), and indirectly the myogenic regulatory factors (MRFs). Specifically, Cdkn1c activation is induced by NF-Y binding to its CCAAT promoter and by reducing the expression of the lncRNA Kcnq1ot1, a negative regulator of Cdkn1c transcription. Overall, our results indicate that NF-YA alternative splicing is an influential muscle cell determinant, through direct regulation of selected cell cycle blocking genes, and, directly and indirectly, of muscle-specific transcription factors.