Congenital human cytomegalovirus (HCMV) infection is the leading cause of neurological disabilities in children worldwide, but the mechanisms underlying these disorders are far from well-defined. HCMV infection has been shown to dysregulate the Notch signaling pathway in human neural progenitor cells (NPCs). As an important downstream effector of Notch signaling, the transcriptional regulator Hairy and Enhancer of Split 1 (Hes1) is essential for governing NPC fate and fetal brain development. In the present study, we report that HCMV infection downregulates Hes1 protein levels in infected NPCs. The HCMV 72-kDa immediate-early 1 protein (IE1) is involved in Hes1 degradation by assembling a ubiquitination complex and promoting Hes1 ubiquitination as a potential E3 ubiquitin ligase, followed by proteasomal degradation of Hes1. Sp100A, an important component of PML nuclear bodies, is identified to be another target of IE1-mediated ubiquitination. A C-terminal acidic region in IE1, spanning amino acids 451 to 475, is required for IE1/Hes1 physical interaction and IE1-mediated Hes1 ubiquitination, but is dispensable for IE1/Sp100A interaction and ubiquitination. Our study suggests a novel mechanism linking downregulation of Hes1 protein to neurodevelopmental disorders caused by HCMV infection. Our findings also complement the current knowledge of herpesviruses by identifying IE1 as the first potential HCMV-encoded E3 ubiquitin ligase.

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Flowering, which plays a crucial role in the growth and development of flowering plants, is a crucial point from vegetative growth to reproductive growth. The goal of this study was to examine the differences between the transcriptomes of the Chinese cabbage mutant pdm and the corresponding wild-type line 'FT'. We performed transcriptome analysis on mRNA isolated from flower buds of pdm and 'FT' using Illumina RNA sequencing (RNA-Seq) data. A total of 117 differentially expressed genes (DEGs) were detected. Among the DEGs, we identified a number of genes involved in floral development and flowering, including an F-box protein gene, EARLY FLOWERING 4 (ELF4), and transcription factors BIGPETAL (BPE) and MYB21 (v-myb avian myeloblastosis viral oncogene homolog); differential expression of these genes could potentially explain the difference in the flowers between pdm and 'FT'. In addition, the expression patterns of 20 DEGs, including 12 floral development and flowering-related genes and eight randomly selected genes, were validated by qRT-PCR, and the results were highly concordant with the RNA-Seq results. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed to better understand the functions of these DEGs. We also identified a large number of single nucleotide polymorphism and insertion/deletion markers, which will be a rich resource for future marker development and breeding research in Chinese cabbage. Also, our analysis revealed numerous novel transcripts and alternative splicing events. The transcriptome analysis provides valuable information for furthering our understanding of the molecular mechanisms that regulate the flowering process, and establishes a solid foundation for future genetic and functional genomic studies in Chinese cabbage.

Pectin-related genes play significant roles in pollen development and pollen tube growth, and their allelic variations are one of the major reasons for the abnormal development of male gametophyte. Currently, little is known about the role of the PMEI family in male sterility of plants. In this study, 97 putative PMEI genes were identified in Brassica rapa genome. By a phylogenetic analysis, the PMEI family was divided into 10 clades with highly conserved structural characteristics. The publically available RNA-seq data on different tissues of B. rapa accession Chiifu-401-42 revealed that 23 PMEI isoforms were flower-specific genes. We created a recessive genic male sterile mutant (ftms) in Chinese cabbage. This mutant was a doubled haploid line with stable inheritance, derived from Chinese cabbage 'FT' generated through a combination of radiation mutagenesis and isolated microspore culture. The transcriptome profiles of the floral buds of ftms and its wild-type line 'FT' were determined using RNA-seq. A total of 17 PMEI genes were found to be differentially expressed; all of them were down-regulated in ftms compared to their levels in 'FT'. Consistent with the transcriptome data, all these genes were observed to be highly expressed in the floral buds of 'FT' using qRT-PCR analysis. Of these, eight genes were specifically expressed in the floral buds of 'FT'; three of these (Bra019903, Bra014099, and Bra032239) were stamen-specific genes. The results contribute to further elucidation of the regulatory mechanisms underlying male sterility in Chinese cabbage.

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Congenital cytomegalovirus (cCMV) infection is the leading infectious cause of neurodevelopmental disorders. However, the neuropathogenesis remains largely elusive due to a lack of informative animal models. In this study, we developed a congenital murine CMV (cMCMV) infection mouse model with high survival rate and long survival period that allowed long-term follow-up study of neurodevelopmental disorders. This model involves in utero intracranial injection and mimics many reported clinical manifestations of cCMV infection in infants, including growth restriction, hearing loss, and impaired cognitive and learning-memory abilities. We observed that abnormalities in MRI/CT neuroimaging were consistent with brain hemorrhage and loss of brain parenchyma, which was confirmed by pathological analysis. Neuropathological findings included ventriculomegaly and cortical atrophy associated with impaired proliferation and migration of neural progenitor cells in the developing brain at both embryonic and postnatal stages. Robust inflammatory responses during infection were shown by elevated inflammatory cytokine levels, leukocyte infiltration, and activation of microglia and astrocytes in the brain. Pathological analyses and CT neuroimaging revealed brain calcifications induced by cMCMV infection and cell death via pyroptosis. Furthermore, antiviral treatment with ganciclovir significantly improved neurological functions and mitigated brain damage as shown by CT neuroimaging. These results demonstrate that this model is suitable for investigation of mechanisms of infection-induced brain damage and long-term studies of neurodevelopmental disorders, including the development of interventions to limit CNS damage associated with cCMV infection.

Leaf color is an important target trait in Chinese cabbage breeding programs. Leaf yellowing may reduce crop commercial and nutritional values. Some plants with the "stay-green" trait maintain leaf greenness during senescence and even after death. Stay-green Chinese cabbage may be a focal point of future breeding projects because it could improve crop quality and yield and prolong shelf life. A new stay-green mutant, non-yellowing mutant 1 (nym1), was identified in Chinese cabbage derived from an ethyl methane sulfonate (EMS)-mutagenized population. The mutant had stay-green characteristics and a higher chlorophyll content than the wild-type during leaf senescence. The staygreen trait in the mutant Chinese cabbage was controlled by the recessive gene Brnym1. MutMap and KASP analyses showed that Brnym1 (BraA03g050600.3C) encodes an mg-dechelatase (SGR protein), which might be the causal gene of the mutation in Chinese cabbage. A nonsynonymous single nucleotide base substitution (G to A) in the third exon of Brnym1 caused an amino acid substitution from L to F in the highly conserved domain of the magnesiumdechelatase. Ectopic overexpression showed that the BrNYM1 gene of wild-type Chinese cabbage complemented the SGR-defective stay-green mutant nye1-1 of Arabidopsis. The magnesium-dechelatase activity in the nym1 mutant was significantly downregulated compared to that in the wild type. Brnym1 was relatively upregulated in the mutant during late senescence, and BrNYM1 was localized to the chloroplasts. These results indicate that Brnym1 (BraA03g050600.3C) is the causal gene of the stay-green mutation and could be of particular significance in the genetic improvement of Chinese cabbage.