Evaluation of the effects of the T-type calcium channel enhancer SAK3 in a rat model of TAF1 deficiency.

The TATA-box binding protein associated factor 1 (TAF1) is part of the TFIID complex that plays a key role during the initiation of transcription. Variants of TAF1 are associated with neurodevelopmental disorders. Previously, we found that CRISPR/Cas9 based editing of the TAF1 gene disrupts the morphology of the cerebral cortex and blunts the expression as well as the function of the CaV3.1 (T-type) voltage gated calcium channel. Here, we tested the efficacy of SAK3 (ethyl 8'-methyl-2', 4-dioxo-2-(piperidin-1-yl)-2'H-spiro [cyclopentane-1, 3'-imidazo [1, 2-a] pyridine]-2-ene-3-carboxylate), a T-type calcium channel enhancer, in an animal model of TAF1 intellectual disability (ID) syndrome. At post-natal day 3, rat pups were subjected to intracerebroventricular (ICV) injection of either gRNA-control or gRNA-TAF1 CRISPR/Cas9 viruses. At post-natal day 21, the rat pups were given SAK3 (0.25 mg/kg, p.o.) or vehicle for 14 days (i.e. till post-natal day 35) and then subjected to behavioral, morphological, and molecular studies. Oral administration of SAK3 (0.25 mg/kg, p.o.) significantly rescued locomotion abnormalities associated with TAF1 gene editing. SAK3 treatment prevented the loss of cortical neurons and GFAP-positive astrocytes observed after TAF1 gene editing. In addition, SAK3 protected cells from apoptosis. SAK3 also restored the Brain-derived neurotrophic factor/protein kinase B/Glycogen Synthase Kinase 3 Beta (BDNF/AKT/GSK3ß) signaling axis in TAF1 edited animals. Finally, SAK3 normalized the levels of three GSK3ß substrates - CaV3.1, FOXP2, and CRMP2. We conclude that the T-type calcium channel enhancer SAK3 is beneficial against the deleterious effects of TAF1 gene-editing, in part, by stimulating the BDNF/AKT/GSK3ß signaling pathway.

Isolation and Characterization of CsWRKY7, a Subgroup IId WRKY Transcription Factor from Camellia sinensis, Linked to Development in Arabidopsis.

WRKY transcription factors (TFs) containing one or two WRKY domains are a class of plant TFs that respond to diverse abiotic stresses and are associated with developmental processes. However, little has been known about the function of WRKY gene in tea plant. In this study, a subgroup IId WRKY gene CsWRKY7 was isolated from Camellia sinensis, which displayed amino acid sequence homology with Arabidopsis AtWRKY7 and AtWRKY15. Subcellular localization prediction indicated that CsWRKY7 localized to nucleus. Cis-acting elements detected in the promotor region of CsWRKY7 are mainly involved in plant response to environmental stress and growth. Consistently, expression analysis showed that CsWRKY7 transcripts responded to NaCl, mannitol, PEG, and diverse hormones treatments. Additionally, CsWRKY7 exhibited a higher accumulation both in old leaves and roots compared to bud. Seed germination and root growth assay indicated that overexpressed CsWRKY7 in transgenic Arabidopsis was not sensitive to NaCl, mannitol, PEG, and low concentration of ABA treatments. CsWRKY7 overexpressing Arabidopsis showed a late-flowering phenotype under normal conditions compared to wild type. Furthermore, gene expression analysis showed that the transcription levels of the flowering time integrator gene FLOWERING LOCUS T (FT) and the floral meristem identity genes APETALA1 (AP1) and LEAFY (LFY) were lower in WRKY7-OE than in the WT. Taken together, these findings indicate that CsWRKY7 TF may participate in plant growth. This study provides a potential strategy to breed late-blooming tea cultivar.

The Arabidopsis TFIID factor AtTAF6 controls pollen tube growth.

Initiation of transcription mediated by RNA polymerase II requires a number of transcription factors among which TFIID is the major core promoter recognition factor. TFIID is composed of highly conserved factors which include the TATA-binding protein (TBP) and about 14 TBP-associated factors (TAFs). Recently, the complete Arabidopsis TAF family has been identified. To obtain functional information about Arabidopsis TAFs, we analyzed a T-DNA insertion mutant for AtTAF6. Segregation analysis showed that plants homozygous for the mutant allele were never found, indicating that inhibition of the AtTAF6 function is lethal. Genetic experiments also revealed that the male gametophyte was affected by the attaf6 mutation since significant reduced transmission of the mutant allele through the male gametophyte was observed. Detailed histological and morphological analysis showed that the T-DNA insertion in AtTAF6 specifically affects pollen tube growth, indicating that the transcriptional regulation of only a specific subset of genes is controlled by this basal transcription factor.