scholarly journals A single amino acid residue substitution in BraA04g017190.3C, a histone methyltransferase, results in premature bolting in Chinese cabbage (Brassica rapa L. ssp. Pekinensis)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chong Tan ◽  
Jie Ren ◽  
Lin Wang ◽  
Xueling Ye ◽  
Wei Fu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Chinese Cabbage ◽  
Nuclear Gene ◽  
Histone Methyltransferase ◽  
Single Amino Acid ◽  
Base Substitution ◽  
Lysine Methylation ◽  
Nonsynonymous Mutation ◽  
Specific Expression ◽  
Single Amino Acid Residue

Abstract Background Flowering is an important inflection point in the transformation from vegetative to reproductive growth, and premature bolting severely decreases crop yield and quality. Results In this study, a stable early-bolting mutant, ebm3, was identified in an ethyl methanesulfonate (EMS)-mutagenized population of a Chinese cabbage doubled haploid (DH) line ‘FT’. Compared with ‘FT’, ebm3 showed early bolting under natural cultivation in autumn, and curled leaves. Genetic analysis showed that the early-bolting phenotype was controlled by a single recessive nuclear gene. Modified MutMap sequencing, genotyping analyses and allelism test provide strong evidence that BrEBM3 (BraA04g017190.3 C), encoding the histone methyltransferase CURLY LEAF (CLF), was the strongly candidate gene of the emb3. A C to T base substitution in the 14th exon of BrEBM3 resulted in an amino acid change (S to F) and the early-bolting phenotype of emb3. The mutation occurred in the SET domain (Suppressor of protein-effect variegation 3–9, Enhancer-of-zeste, Trithorax), which catalyzes site- and state-specific lysine methylation in histones. Tissue-specific expression analysis showed that BrEBM3 was highly expressed in the flower and bud. Promoter activity assay confirmed that BrEBM3 promoter was active in inflorescences. Subcellular localization analysis revealed that BrEBM3 localized in the nucleus. Transcriptomic studies supported that BrEBM3 mutation might repress H3K27me3 deposition and activate expression of the AGAMOUS (AG) and AGAMOUS-like (AGL) loci, resulting in early flowering. Conclusions Our study revealed that an EMS-induced early-bolting mutant ebm3 in Chinese cabbage was caused by a nonsynonymous mutation in BraA04g017190.3 C, encoding the histone methyltransferase CLF. These results improve our knowledge of the genetic and genomic resources of bolting and flowering, and may be beneficial to the genetic improvement of Chinese cabbage.

scholarly journals A Single Amino Acid Change In Histone Methyltransferase CURLY LEAF Results In Premature Bolting In Chinese Cabbage (Brassica Rapa L. Ssp. Pekinensis)

2021 ◽  
Author(s):  
Chong Tan ◽  
Jie Ren ◽  
Lin Wang ◽  
Xueling Ye ◽  
Wei Fu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Chinese Cabbage ◽  
Amino Acid Change ◽  
Nuclear Gene ◽  
Histone Methyltransferase ◽  
Single Amino Acid ◽  
Base Substitution ◽  
Nonsynonymous Mutation ◽  
Single Amino Acid Change ◽  
Curly Leaf

Abstract Background: Flowering is an important inflection point in the transformation from vegetative to reproductive growth, and premature bolting severely decreases crop yield and quality. Results: In this study, a stable early-bolting mutant, ebm3, was identified in an ethyl methanesulfonate (EMS)-mutagenized population of a Chinese cabbage doubled haploid (DH) line ‘FT’. Compared with ‘FT’, ebm3 showed early bolting under natural cultivation in autumn, and curled leaves. Genetic analysis showed that the early-bolting phenotype was controlled by a single recessive nuclear gene. Modified MutMap and genotyping analyses revealed that Brebm3 (BraA04g017190.3C), encoding the histone methyltransferase CURLY LEAF (CLF), was the causal gene of the emb3. A C to T base substitution in the 14th exon of Brebm3 resulted in an amino acid change (S to F) and the early-bolting phenotype of emb3. The mutation occurred in the SET domain (Suppressor of protein-effect variegation 3-9, Enhancer-of-zeste, Trithorax), which catalyzes site- and state-specific lysine methylation in histones. Tissue-specific expression analysis showed that Brebm3 was highly expressed in the flower and bud. Promoter activity assay confirmed that Brebm3 promoter was active in inflorescences. Subcellular localization analysis revealed that Brebm3 localized in the nucleus. Transcriptomic studies supported that Brebm3 mutation might repress H3K27me3 deposition and activate expression of the AGAMOUS (AG) and AGAMOUS-like (AGL) loci, resulting in early flowering.Conclusions: Our study revealed that an EMS-induced early-bolting mutant ebm3 in Chinese cabbage was caused by a nonsynonymous mutation in BraA04g017190.3C, encoding the histone methyltransferase CLF.These results improve our knowledge of the genetic and genomic resources of bolting and flowering, and may be beneficial to the genetic improvement of Chinese cabbage.

scholarly journals Pathogenic alleles in microtubule, secretory granule and extracellular matrix-related genes in familial keratoconus

2021 ◽  
Author(s):  
Vishal Shinde ◽  
Nara Sobreira ◽  
Elizabeth S Wohler ◽  
George Maiti ◽  
Nan Hu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Cultures ◽  
Cell Biology ◽  
Stromal Cell ◽  
Primary Cilia ◽  
Single Amino Acid ◽  
European Ancestry ◽  
Base Substitution ◽  
Amino Acid Substitutions ◽  
Functional Link

Abstract Keratoconus is a common corneal defect with a complex genetic basis. By whole exome sequencing of affected members from 11 multiplex families of European ancestry, we identified 23 rare, heterozygous, potentially pathogenic variants in 8 genes. These include nonsynonymous single amino acid substitutions in HSPG2, EML6 and CENPF in two families each, and in NBEAL2, LRP1B, PIK3CG and MRGPRD in three families each; ITGAX had nonsynonymous single amino acid substitutions in two families and an indel with a base substitution producing a nonsense allele in the third family. Only HSPG2, EML6 and CENPF have been associated with ocular phenotypes previously. With the exception of MRGPRD and ITGAX, we detected the transcript and encoded protein of the remaining genes in the cornea and corneal cell cultures. Cultured stromal cells showed cytoplasmic punctate staining of NBEAL2, staining of the fibrillar cytoskeletal network by EML6, while CENPF localized to the basal body of primary cilia. We inhibited the expression of HSPG2, EML6, NBEAL2 and CENPF in stromal cell cultures and assayed for the expression of COL1A1 as a readout of corneal matrix production. An upregulation in COL1A1 after siRNA inhibition indicated their functional link to stromal cell biology. For ITGAX, encoding a leukocyte integrin, we assayed its level in the sera of 3 affected families compared with 10 unrelated controls to detect an increase in all affecteds. Our study identified genes that regulate the cytoskeleton, protein trafficking and secretion, barrier tissue function and response to injury and inflammation, as being relevant to keratoconus.

scholarly journals The medaka fish Tol2 transposable element is in an early stage of decay: identification of a nonautonomous copy

Genome ◽  
2021 ◽  
Author(s):  
Sakura Hayashi ◽  
Takuji Tsukiyama ◽  
Atsuo Iida ◽  
Masato Kinoshita ◽  
Akihiko Koga
Keyword(s):  
Amino Acid ◽  
Stop Codon ◽  
Early Stage ◽  
Single Amino Acid ◽  
Base Substitution ◽  
Unique Element ◽  
Medaka Fish ◽  
Medaka Genome ◽  
Single Amino Acid Change ◽  
Local Sequence

The majority of DNA-based transposable elements comprise autonomous and nonautonomous copies, or only nonautonomous copies, where the autonomous copy contains an intact gene for a transposase protein and the nonautonomous copy does not. Even if autonomous copies coexist, they are generally less frequent. The <i>Tol2</i> element of medaka fish is one of the few elements for which a nonautonomous copy has not yet been found. Here we report the presence of a nonautonomous <i>Tol2</i> copy that was identified by surveying the medaka genome sequence database. This copy contained 3 local sequence alterations that affected the deduced amino acid sequence of the transposase: a deletion of 15 nucleotides resulting in a deletion of 5 amino acids, a base substitution causing a single amino acid change, and another base substitution giving rise to a stop codon. Transposition assays using cultured human cells revealed that the transposase activity was reduced by the 15-nucleotide deletion and abolished by the nonsense mutation. This is the first example of a nonautonomous <i>Tol2</i> copy. Thus, <i>Tol2</i> is in an early stage of decay in the medaka genome, and is therefore a unique element to observe an almost whole decay process that progresses in natural populations.

scholarly journals Effect of single amino acid substitutions on the formation of the PlA and Bak alloantigenic epitopes

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 681-687 ◽  
Author(s):  
A Goldberger ◽  
M Kolodziej ◽  
M Poncz ◽  
JS Bennett ◽  
PJ Newman
Keyword(s):  
Amino Acid ◽  
Expression System ◽  
Single Amino Acid ◽  
Expression Vectors ◽  
Membrane Glycoproteins ◽  
Amino Acid Polymorphism ◽  
Specific Expression ◽  
Mammalian Expression ◽  
Single Amino Acid Polymorphisms ◽  
Necessary And Sufficient

Abstract The subunits that comprise the platelet-specific integrin alpha IIb beta 3 are polymorphic in nature, with several allelic forms present in the human gene pool. Minor changes in the secondary and tertiary structures of platelet membrane glycoproteins (GP) IIb and IIIa encoded by these alleles can result in an alloimmune reaction after transfusion or during pregnancy. To better understand the molecular structure of the PlA alloantigen system, located on GPIIIa, and the Bak alloantigen on GPIIb, we used a heterologous mammalian expression system to express these integrin subunits in their known polymorphic forms. An expression vector containing the PlA1 form of a GPIIIa cDNA, which encodes a leucine at amino acid 33 (Leu33), was modified to express the PlA2- associated form encoding a proline at amino acid 33 (Pro33). Similarly, a Baka GPIIb cDNA expressing an isoleucine at amino acid 843 (IIe843) was modified to express the Bakb form containing a serine at the same position (Ser843). Transfection of these vectors into COS cells resulted in the synthesis of GPIIb and GPIIIa molecules that were identical in size to those present in platelet lysates. Immunoprecipitation of the GPIIIa-transfected COS lysates with PlA)- specific alloantisera indicated that the Leu33 form was recognized only by anti-PIA1 sera while the Pro33 form was bound only by anti-PlA2 sera, showing that single amino acid polymorphisms are necessary and sufficient to direct the formation of the PlA1 and PlA2 alloepitopes. Similar experiments with Bak allele-specific expression vectors indicated that while the amino acid polymorphism (IIe843 in equilibrium Ser843) was necessary, posttranslational processing of pro-IIb was required for efficient exposure of both the Baka and Bakb alloepitopes.

scholarly journals Three Drosophila beta-tubulin sequences: a developmentally regulated isoform (beta 3), the testis-specific isoform (beta 2), and an assembly-defective mutation of the testis-specific isoform (B2t8) reveal both an ancient divergence in metazoan isotypes and structural constraints for beta-tubulin function.

1987 ◽  
Vol 7 (6) ◽  
pp. 2231-2242 ◽  
Author(s):  
J E Rudolph ◽  
M Kimble ◽  
H D Hoyle ◽  
M A Subler ◽  
E C Raff
Keyword(s):  
Amino Acid ◽  
Sequence Divergence ◽  
Amino Acid Sequences ◽  
Single Amino Acid ◽  
Structural Constraints ◽  
Wild Type ◽  
Beta Tubulin ◽  
Developmentally Regulated ◽  
Single Amino Acid Residue ◽  
Beta 2

The genomic DNA sequence and deduced amino acid sequence are presented for three Drosophila melanogaster beta-tubulins: a developmentally regulated isoform beta 3-tubulin, the wild-type testis-specific isoform beta 2-tubulin, and an ethyl methanesulfonate-induced assembly-defective mutation of the testis isoform, B2t8. The testis-specific beta 2-tubulin is highly homologous to the major vertebrate beta-tubulins, but beta 3-tubulin is considerably diverged. Comparison of the amino acid sequences of the two Drosophila isoforms to those of other beta-tubulins indicates that these two proteins are representative of an ancient sequence divergence event which at least preceded the split between lines leading to vertebrates and invertebrates. The intron/exon structures of the genes for beta 2- and beta 3-tubulin are not the same. The structure of the gene for the variant beta 3-tubulin isoform, but not that of the testis-specific beta 2-tubulin gene, is similar to that of vertebrate beta-tubulins. The mutation B2t8 in the gene for the testis-specific beta 2-tubulin defines a single amino acid residue required for normal assembly function of beta-tubulin. The sequence of the B2t8 gene is identical to that of the wild-type gene except for a single nucleotide change resulting in the substitution of lysine for glutamic acid at residue 288. This position falls at the junction between two major structural domains of the beta-tubulin molecule. Although this hinge region is relatively variable in sequence among different beta-tubulins, the residue corresponding to glu 288 of Drosophila beta 2-tubulin is highly conserved as an acidic amino acid not only in all other beta-tubulins but in alpha-tubulins as well.

scholarly journals Single amino acid residue as a functional determinant of rod and cone visual pigments

1997 ◽  
Vol 94 (6) ◽  
pp. 2322-2326 ◽  
Author(s):  
H. Imai ◽  
D. Kojima ◽  
T. Oura ◽  
S. Tachibanaki ◽  
A. Terakita ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Residue ◽  
Visual Pigments ◽  
Single Amino Acid ◽  
Functional Determinant ◽  
Single Amino Acid Residue

scholarly journals Genotypic Differences in Dengue Virus Neutralization Are Explained by a Single Amino Acid Mutation That Modulates Virus Breathing

mBio ◽  
2015 ◽  
Vol 6 (6) ◽  
Author(s):  
Kimberly A. Dowd ◽  
Christina R. DeMaso ◽  
Theodore C. Pierson
Keyword(s):  
Amino Acid ◽  
Dengue Virus ◽  
Vaccine Development ◽  
Antibody Binding ◽  
Single Amino Acid ◽  
Genotypic Differences ◽  
Conformational Ensembles ◽  
Single Amino Acid Residue ◽  
Virus Serotype ◽  
Serotype 1

ABSTRACTFlaviviruses sample an ensemble of virion conformations resulting from the conformational flexibility of their structural proteins. To investigate how sequence variation among strains impacts virus breathing, we performed studies with the monoclonal antibody (MAb) E111, which binds an inaccessible domain III envelope (E) protein epitope of dengue virus serotype 1 (DENV1). Prior studies indicated that an observed ~200-fold difference in neutralization between the DENV1 strains Western Pacific-74 (West Pac-74) and 16007 could not be explained by differences in the affinity of MAb E111 for each strain. Through neutralization studies with wild-type and variant viruses carrying genes encoding reciprocal mutations at all 13 amino acid differences between the E proteins of West Pac-74 and 16007, we found that E111 neutralization susceptibility mapped solely to the presence of a lysine or arginine at E domain II residue 204, located distally from the E111 epitope. This same residue correlated with neutralization differences observed for MAbs specific for epitopes distinct from E111, suggesting that this amino acid dictates changes in the conformational ensembles sampled by the virus. Furthermore, an observed twofold difference in the stability of infectious West Pac-74 versus 16007 in solution also mapped to E residue 204. Our results demonstrate that neutralization susceptibility can be altered in an epitope-independent manner by natural strain variation that influences the structures sampled by DENV. That different conformational ensembles of flaviviruses may affect the landscape available for antibody binding, as well as virus stability, has important implications for functional studies of antibody potency, a critical aspect of vaccine development.IMPORTANCEThe global burden of dengue virus (DENV) is growing, with recent estimates of ~390 million human infections each year. Antibodies play a crucial role in protection from DENV infection, and vaccines that elicit a robust antibody response are being actively pursued. We report here the identification of a single amino acid residue in the envelope protein of DENV serotype 1 that results in global changes to virus structure and stability when it is changed. Our results indicate that naturally occurring variation at this particular site among virus strains impacts the ensemble of structures sampled by the virus, a process referred to as virus breathing. The finding that such limited and conservative sequence changes can modulate the landscape available for antibody binding has important implications for both vaccine development and the study of DENV-reactive antibodies.

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