The FAcilitates Chromatin Transcription complex regulates the ratio of glycolysis to oxidative phosphorylation in neural stem cells

Defects in the FAcilitates Chromatin Transcription(FACT)complex,a histone chaperone composed of SSRP1 and SUPT16H,are implicated in intellectual disability.Here,we reveal that the FACT complex promotes glycolysis and sustains the correct cell fate of neural stem cells/neuroblasts in the Drosophila 3rd instar larval central brain.We show that the FACT complex binds to the promoter region of the estrogen-related receptor(ERR)gene and positively regulates ERR expression.ERR is known to act as an aerobic glycolytic switch by upregulating the enzymes required for glycolysis.Dysfunction of the FACT complex leads to the downregulation of ERR transcription,resulting in a decreased ratio of glycolysis to oxidative phosphorylation(G/O)in neuroblasts.Consequently,neuroblasts exhibit smaller cell sizes,lower proliferation potential,and altered cell fates.Overexpression of ERR or suppression of mitochondrial oxidative phosphorylation in neuroblasts increases the relative G/O ratio and rescues defective phenotypes caused by dysfunction of the FACT complex.Thus,the G/O ratio,mediated by the FACT complex,plays a crucial role in neuroblast cell fate maintenance.Our study may shed light on the mechanism by which mutations in the FACT complex lead to intellectual disability in humans.

PIF4 interacts with ABI4 to serve as a transcriptional activator complex to promote seed dormancy by enhancing ABA biosynthesis and signaling

Transcriptional regulation plays a key role in the control of seed dormancy,and many transcription factors(TFs)have been documented.However,the mechanisms underlying the interactions between different TFs within a transcriptional complex regulating seed dormancy remain largely unknown.Here,we showed that TF PHYTOCHROME-INTERACTING FACTOR4(PIF4)physically interacted with the abscisic acid(ABA)signaling responsive TF ABSCISIC ACID INSENSITIVE4(ABI4)to act as a transcriptional complex to promote ABA biosynthesis and signaling,finally deepening primary seed dormancy.Both pif4 and abi4 single mutants exhibited a decreased primary seed dormancy phenotype,with a synergistic effect in the pif4/abi4 double mutant.PIF4 binds to ABI4 to form a heterodimer,and ABI4 stabilizes PIF4 at the protein level,whereas PIF4 does not affect the protein stabilization of ABI4.Subsequently,both TFs independently and synergistically promoted the expression of ABI4 and NCED6,a key gene for ABA anabolism.The genetic evidence is also consistent with the phenotypic,physiological and biochemical analysis results.Altogether,this study revealed a transcriptional regulatory cascade in which the PIF4–ABI4 transcriptional activator complex synergistically enhanced seed dormancy by facilitating ABA biosynthesis and signaling.

Regulatory mechanisms of iron homeostasis in maize mediated by ZmFIT

Regulation of iron homeostasis in maize remains unclear,despite the known roles of FER-Like Fe deficiency-induced transcription factor(FIT)in Arabidopsis and rice.ZmFIT,like At FIT and Os FIT,interacts with iron-related transcription factors 2(ZmIRO2).Here,we investigate the involvement of ZmFIT in iron homeostasis.Mutant ZmFIT lines exhibiting symptoms of Fe deficiency had reduced shoot iron content.Transcriptome analysis revealed downregulation of Fe deficiency-responsive genes in the roots of a Zmfit mutant.ZmFIT facilitates the nuclear translocation of ZmIRO2 to activate transcription of downstream genes under Fe-deficient conditions.Our findings suggest that ZmFIT,by interaction with ZmIRO2,mediates iron homeostasis in maize.Notably,the binding and activation mechanisms of ZmFIT resemble those in Arabidopsis but differ from those in rice,whereas downstream genes regulated by ZmFIT show similarities to rice but differences from Arabidopsis.In brief,ZmFIT,orthgologs of Os FIT and At FIT in rice and maize,respectively,regulates iron uptake and homeostasis in maize,but with variations.

Structural components of the nuclear body in nuclei of Allium cepa cells

Nuclear bodies have long been noted in interphase nuclei of plant cells, but their structural component, origin and function are still unclear by now. The present work showed in onion cells the nuclear bodies appeared as a spherical structure about 0.3 to 0.8 microm in diameter. They possibly were formed in nucleolus and subsequently released, and entered into nucleoplasm. Observation through cytochemical staining method at the ultrastructural level confirmed that nuclear bodies consisted of ribonucleoproteins (RNPs) and silver-stainable proteins. Immunocytochemical results revealed that nuclear bodies contained no DNA and ribosomal gene transcription factor (UBF). Based on these data, we suggested that nuclear bodies are not related to the ribosome or other gene transcription activities, instead they may act as subnuclear structures for RNPs transport from nucleolus to cytoplasm, and may also be involved in splicing of pre-mRNAs.

Transcriptional regulation of phospholipid transport in cotton fiber elongation by GhMYB30D04–GhHD1 interaction complex

Cotton fiber length is basically determined by wellcoordinated gene expression and phosphatidylinositol phosphates(PIPs) accumulation during fiber elongation but the regulatory mechanism governing PIPs transport remains unknown.Here,we report a MYB transcription factor GhMYB30D04 in Gossypium hirsutum that promotes fiber elongation through modulating the expression of PIP transporter gene GhLTPG1.Knockout of GhMYB30D04gene in cotton(KO) results in a reduction of GhLTPG1 transcripts with lower accumulation of PIPs,leading to shorter fibers and lower fiber yield.Conversely,GhMYB30D04 overexpression(GhMYB30D04-OE) causes richer PIPs and longer cotton fibers,mimicking the effects of exogenously applying PIPs on the ovules of GhMYB30D04-KO and wild type.Furthermore,GhMYB30D04 interacts with GhHD1,the crucial transcription factor of fiber initiation,to form an activation complex stabilized by PIPs,both of which upregulate GhLTPG1 expression.Comparative omics-analysis revealed that higher and extended expressions of LTPG1 in fiber elongation mainly correlate with the variations of the GhMYB30D04 gene between two cotton allotetraploids,contributing to longer fiber in G.babardense.Our work clarifies a mechanism by which GhHD1–GhMYB30D04 form a regulatory module of fiber elongation to tightly control PIP accumulation.Our work still has an implication that GhMYB30D04–GhHD1 associates with development transition from fiber initiation to elongation.