A sulfotransferase gene BnSOT-like1 has a minor genetic effect on seed glucosinolate content in Brassica napus

The theory and associated selection methods of classical quantitative genetics are based on the multifactorial or polygene hypothesis.Major genes or quantitative trait loci(QTL)in modern quantitative genetics based on a“major gene plus polygenes”genetic system have been paid much attention in genetic studies.However,it remains unclear how the numerous minor genes act,although the polygene theory has sustained genetic improvement in plants and animals for more than a hundred years.In the present study,we identified a novel minor gene,BnSOT-like1(BnaA09g53490D),which is a sulfotransferase(SOT)gene catalyzing the formation of the core glucosinolate(GSL)structure in Brassica napus.This gene has been occasionally found during investigations of plant height-related genes,but has not been identified by QTL mapping because of its small phenotypic effects on GSL content.The overexpression of BnSOT-like1 up-regulated the expression of aliphatic GSL-associated genes,leading to a high seed aliphatic GSL content,and the overexpression of the allelic gene Bnsot-like1 did not increase seed GSL content.These findings suggest that the SOT gene has a marked effect on a quantitative trait from a reverse genetics standpoint,but a minor effect on the quantitative trait in its natural biological state.Because of the redundancy of GSL biosynthetic genes in the allotetraploid species B.napus,mutations of a single functional gene in the pathway will not result in significant phenotypic changes,and that the genes in biosynthetic pathways such as BnSOT-like1 in our study have minor effects and may be called polygenes in contrast to the reported three regulatory genes(BnHAG1s)which strongly affect GSL content in B.napus.The present study has shed light on a minor gene for a quantitative trait.

Tyrosylprotein sulfotransferase suppresses ABA signaling via sulfation of SnRK2.2/2.3/2.6

Phytohormone abscisic acid(ABA)plays vital roles in stress tolerance,while long-term overactivation of ABA signaling suppresses plant growth and development.However,the braking mechanism of ABA responses is not clear.Protein tyrosine sulfation catalyzed by tyrosylprotein sulfotransferase(TPST)is a critical post-translational modification.Through genetic screening,we identified a tpst mutant in Arabidopsis that was hypersensitive to ABA.In-depth analysis revealed that TPST could interact with and sulfate SnRK2.2/2.3/2.6,which accelerated their degradation and weakened the ABA signaling.Taken together,these findings uncovered a novel mechanism of desensitizing ABA responses via protein sulfation.

The interplay between hepatocyte nuclear factor 4α(HNF4α)and cholesterol sulfotransferase(SULT2B1b)in hepatic energy homeostasis

The nuclear receptor hepatocyte nuclear factor 4alpha(HNF4α)plays a critical role in the regulation of metabolic homeostasis,including glucose homeostasis.Sulfotransferases(SULTs)catalyze the transfer of a sulfate group from 3-phosphoadenosine 5-phosphosulfate(PAPS)to an acceptor molecule.Sulfonation plays an essential role in regulating the chemical and functional homeostasis of endogenous and exogenous molecules.Among SULTs,the cholesterol sulfotransferase 2B1b(SULT2B1b)preferentially catalyzes the sulfoconjugation of cholesterol and oxysterols to form cholesterol sulfate and oxysterol sulfates.Hepatic gluconeogenesis represents a critical component of energy metabolism.Although there have been reviews on the regulation of glucose homeostasis by HNF4a,the interplay between HNF4a and SULT2B1b in hepatic glucose homeostasis remains scattered.In this review,we intend to provide an overview on how HNF4a functionally cross-talks with SULT2B1b to regulate hepatic glucose homeostasis and whether the HNF4a-SULT2B1b axis represents a novel therapeutic target for the management of metabolic liver disease and metabolic syndrome.

Arenobufagin is a novel isoform-specific probe for sensing human sulfotransferase 2A1

Human cytosolic sulfotransferase 2 A1(SULT2A1) is an important phase II metabolic enzyme. The detection of SULT2A1 is helpful for the functional characterization of SULT2A1 and diagnosis of its related diseases. However, due to the overlapping substrate specificity among members of the sulfotransferase family, it is difficult to develop a probe substrate for selective detection of SULT2A1. In the present study, through characterization of the sulfation of series of bufadienolides, arenobufagin(AB) was proved as a potential probe substrate for SULT2A1 with high sensitivity and specificity. Subsequently, the sulfation of AB was characterized by experimental and molecular docking studies. The sulfate-conjugated metabolite was identified as AB-3-sulfate.The sulfation of AB displayed a high selectivity for SULT2A1 which was confirmed by in vitro reaction phenotyping assays. The sulfation of AB by human liver cytosols and recombinant SULT2A1 both obeyed Michaelis-Menten kinetics, with similar kinetic parameters. Molecular docking was performed to understand the interaction between AB and SULT2A1, in which the lack of interaction with Met-137 and Tyr-238 of SULT2A1 made it possible to eliminate substrate inhibition of AB sulfation. Finally, the probe was successfully used to determine the activity of SULT2A1 and its isoenzymes in tissue preparations of human and laboratory animals.

Pathogenic mutations of TGFBI and CHST6 genes in Chinese patients with Avellino,lattice,and macular corneal dystrophies

Objective:To investigate gene mutations associated with three different types of corneal dystrophies(CDs),and to establish a phenotype-genotype correlation.Methods:Two patients with Avellino corneal dystrophy(ACD),four patients with lattice corneal dystrophy type I(LCD I) from one family,and three patients with macular corneal dystrophy type I(MCD I) were subjected to both clinical and genetic examinations.Slit lamp examination was performed for all the subjects to assess their corneal phenotypes.Genomic DNA was extracted from peripheral blood leukocytes.The coding regions of the human transforming growth factor β-induced(TGFBI) gene and carbohydrate sulfotransferase 6(CHST6) gene were amplified by polymerase chain reaction(PCR) and subjected to direct sequencing.DNA samples from 50 healthy volunteers were used as controls.Results:Clinical examination showed three different phenotypes of CDs.Genetic examination identified that two ACD subjects were associated with homozygous R124H mutation of TGFBI,and four LCD I subjects were all associated with R124C heterozygous mutation.One MCD I subject was associated with a novel S51X homozygous mutation in CHST6,while the other two MCD I subjects harbored a previously reported W232X homozygous mutation.Conclusions:Our study highlights the prevalence of codon 124 mutations in the TGFBI gene among the Chinese ACD and LCD I patients.Moreover,we found a novel mutation among MCD I patients.

Genetics and pathophysiology of mammalian sulfate biology

Nutrient sulfate is essential for numerous physiological functions in mammalian growth and development.Accordingly,disruptions to any of the molecular processes that maintain the required biological ratio of sulfonated and unconjugated substrates are likely to have detrimental consequences for mammalian physiology.Molecular processes of sulfate biology can be broadly grouped into four categories:firstly,intracellular sulfate levels are maintained by intermediary metabolism and sulfate transporters that mediate the transfer of sulfate across the plasma membrane;secondly,sulfate is converted to 3'-phosphoadenosine 5'-phosphosulfate(PAPS),which is the universal sulfonate donor for all sulfonation reactions;thirdly,sulfotransferases mediate the intracellular sulfonation of endogenous and exogenous substrates;fourthly,sulfate is removed from substrates via sulfatases.From the literature,we curated 91 human genes that encode all known sulfate transporters,enzymes in pathways of sulfate generation,PAPS synthetases and transporters,sulfotransferases and sulfatases,with a focus on genes that are linked to human and animal pathophysiology.The predominant clinical features linked to these genes include neurological dysfunction,skeletal dysplasias,reduced fecundity and reproduction,and cardiovascular pathologies.Collectively,this review provides reference information for genetic investigations of perturbed mammalian sulfate biology.