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Crystallographic characterization of wild-type and mutant ribonuclease T1 complexes with several ribonucleotides.

Ribonuclease T1 and the mutant enzymes were cocrystallized with several ribonucleotides, including non-hydrolyzable substrate analogs of di- and triribonucleotides, which have a novel guanylate in which the 2'-hydroxyl group of the ribose is replaced by a fluorine atom. One of the mutant enzymes has a tryptophan residue, instead of Tyr45 of the wild-type enzyme, to enhance the binding of ribonucleotides to the enzyme and the other mutant enzyme has histidine and aspartate residues, instead of Asn43 and Asn44, respectively, to reproduce the natural substitutions found in ribonuclease Ms. Polymorphism of the crystals was observed for wild-type and mutant enzymes. However, orthorhombic crystals, which are virtually all isomorphous to each other, were successfully obtained from wild-type and mutant (Y45W) enzymes by the macroscopic seeding technique using mother crystals of the wild-type ribonuclease T1 complexed with 2'GMP or 3'GMP. The diffraction patterns of these crystals extend beyond 2.5 A resolution and the diffraction data were collected from some of the crystals on a diffractometer up to a range of 2.5 to 1.8 A resolution.

Aspergillus oryzae

Bovine mitochondrial DNA polymorphism in restriction endonuclease cleavage patterns and the location of the polymorphic sites.

Cleavage patterns of mitochondrial DNA (mtDNA) by restriction endonuclease analysis were examined in four Japanese Black cows, three Japanese Shorthorn cows, and six Holstein cows. Seventeen restriction enzymes which recognize six base pairs and two restriction enzymes which recognize four base pairs were used in this study. Polymorphism was observed with three restriction enzymes, HindIII, TaqI, and MspI, and was detected within the breeds. Nucleotide substitution was determined in the HindIII polymorphic site by DNA cloning and sequencing; this is C----T at position 10126 of the URF-3 region. Furthermore, the MspI and TaqI polymorphic sites were located on the physical map.

Animals

Pelizaeus-Merzbacher disease: detection of mutations Thr181----Pro and Leu223----Pro in the proteolipid protein gene, and prenatal diagnosis.

A family with an apparent history of X-linked Pelizaeus-Merzbacher disease presented for genetic counseling, requesting carrier detection and prenatal diagnosis. RFLP analysis using the proteolipid protein (PLP) gene probe was uninformative in this family. A prenatal diagnosis on a chorionic villus sample (CVS) was carried out using single-strand conformation polymorphism (SSCP) analysis of a variant in exon 4 of the PLP gene. The fetus was predicted to be unaffected. Sequencing of the exon from the CVS, the predicted-carrier mother, and the obligate-carrier grandmother revealed an A-to-C change at nucleotide 541 in the two women but not in the fetus. As this change results in a Thr-to-Pro change at amino acid 181 in a region of the gene predicted to be part of a transmembrane segment, it was concluded that this was the mutation causing the disease in this family. In addition, in a second family, an exon 5 variant band pattern on SSCP analysis was shown by sequencing to be due to a T-to-C change at nucleotide 668. This results in a Leu-to-Pro change in a carrier mother and in her two affected sons. These results provide further examples of mutations in PLP that cause Pelizaeus-Merzbacher disease and illustrate the value of SSCP in genetic analysis.

Amino Acid Sequence

Neutralization-sensitive merozoite surface antigens of Babesia bovis encoded by members of a polymorphic gene family.

Monospecific antibodies against native and recombinant versions of the major merozoite surface antigen (MSA-1) of Babesia bovis neutralize the infectivity of merozoites from Texas and Mexico strains in vitro. Sequence analysis shows that MSA-1 and a related, co-expressed 44 kDa merozoite surface protein (MSA-2) are encoded by members of a multigene family previously designated BabR. BabR genes, originally described in Australia strains of B. bovis, are notable because their marked polymorphism is apparently mediated by chromosomal rearrangements, but protein products of BabR genes have not previously been identified. The 3' terminal 173 nucleotides of the MSA-1 gene, including 60 nucleotides of untranslated sequence, are highly similar to the 3' terminal sequences of BabR 0.8 (84% identity) and MSA-2 (94% identity). Alignment of the predicted protein sequences demonstrates significant overall homology between MSA-1 and MSA-2, and between both proteins and the amino terminal BabR sequence. MSA-1 nucleic acid probes also hybridize weakly to genomic DNA from the Australia 'L' strain, even though this strain does not express merozoite surface epitopes cross-reactive with MSA-1 or MSA-2. Hybridization of these same probes to genomic DNA from the cloned Mexico strain reveals a pattern of bands compatible with two copies each of MSA-1 and MSA-2. Proteins encoded by this B. bovis gene family have been designated variable merozoite surface antigens (VMSA). The extent and mechanism of VMSA polymorphism among strains will be important when evaluating the role these surface proteins have in the host-parasite interaction, including immunity to blood stages.

Amino Acid Sequence

Genome-wide association studies with experimental validation identify a protective role for B lymphocytes against chronic post-surgical pain.

BACKGROUND: Chronic post-surgical pain (CPSP) significantly impacts patients' recovery and quality of life. Although environmental risk factors are well-established, genetic risk remains less understood. METHODS: A meta-analysis of genome-wide association studies followed by partitioned heritability was performed on 1350 individuals across five surgery types: hysterectomy, mastectomy, abdominal, hernia, and knee. In subsequent animal studies, withdrawal thresholds to evoked mechanical stimulation were measured in Rag1 null mutant and wild-type mice after plantar incision and laparotomy. Cell sorting by flow cytometry tracked recruitment of immune cell types. RESULTS: We discovered 77 genome-wide significant single-nucleotide polymorphism (SNP) hits, distributed among 24 loci and 244 genes. Meta-analysis of all cohorts estimated a SNP-based narrow-sense heritability for CPSP at ∼39%, indicating a substantial genetic contribution. Partitioned heritability analysis across a wide variety of tissues revealed enrichment of heritability in immune system-related genes, particularly those associated with B and T cells. Rag1 null mutant mice lacking both T and B cells exhibited exacerbated and prolonged allodynia up to 42 days after surgery, which was rescued by B-cell transfer. Recruitment patterns of B cells but not T cells differed significantly during the first 7 days after injury in the footpad, lymph nodes, and dorsal root ganglia. CONCLUSIONS: These findings suggest a key protective role for the adaptive immune system in the development of chronic post-surgical pain.

Animals

HLA class II typing by digestion of PCR-amplified DNA with allele-specific restriction endonucleases will fail to unequivocally identify the genotypes of many homozygous and heterozygous individuals.

Recently, a new technique for HLA class II genotyping has been introduced, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, claimed to be a practical alternative to conventional serological and cellular HLA class II typing (1-3). The PCR-RFLP technique is ingenious, relatively rapid and does not require hybridization with sequence-specific oligonucleotide probes. However, analysis of whether homozygous and heterozygous combinations of PCR-RFLP patterns for the various investigated HLA class II loci are unique or not unfortunately shows that only 19% of DRB homozygous and heterozygous combinations are unique. The figures for the DQA1, DQB and DPB loci are 56%, 29% and 65%, respectively. As not all nucleotide sequences analyzed in the above-mentioned studies (1-3) gave rise to unique PCR-RFLPs and as more sequences now are known, for the DRB1, DRB3, DRB5 and DPB1 loci (4), the frequencies of unique PCR-RFLP patterns for the different HLA class II loci will be reduced even further. Thus, the present analysis demonstrates that the PCR-RFLP technique, performed as described in references 1-3, is not yet ready to be used for routine HLA class II genotyping. The resolution of the PCR-RFLP method can be improved by various modifications. However, the role of a modified PCR-RFLP technique in HLA class II typing still remains to be shown.

Alleles

p53 mutations in ovarian cancer: a late event?

Using a combination of polymerase chain reaction and single-strand conformation polymorphism techniques we analyzed 34 ovarian cancer samples (30 primary tumors and four matched metastases) for the presence of mutations in exons 5, 6, 7, 8 and 9 of the p53 gene. Mutations in this portion of the gene are known to lead to the loss of the oncosuppressive potential of p53. Thirty-six percent (11/30) of the ovarian carcinomas tested presented a mutated p53 allele. Mutations were clustered in exons 5 and 7 to the exclusion of the other exons screened. Most mutations (10/11) were point mutations, but no preferential pattern of nucleotide substitution could be observed. In three tumors the mutation of one allele was concomitant with the loss of the wild-type counterpart. Another sample presented both alleles independently mutated. These observations are in agreement with the recessive nature of the p53 mutation. However, analysis of tissue sections from two tumors showed that the portion composed of 100% cancer cells could hold both the mutated and the wild-type form. Moreover analysis of serial sections gave evidence of a heterogeneous cellular content in one of these tumors, suggesting that p53 mutations may, in some cases, occur late during ovarian cancer evolution. It is, moreover, noticeable that, in matched sets of primary tumors and metastases, the same mutation was observed in both tumor samples. Therefore, even as a late event, p53 mutation occurs before metastatic spread.

Amino Acid Sequence

Detection of genomic variation in Providencia stuartii clinical isolates by analysis of DNA restriction fragment length polymorphisms containing rRNA cistrons.

Chromosomal DNA from 26 strains of Providencia stuartii isolated mainly in hospitals in the United Kingdom and reference strains of P. stuartii, P. rustigianii, and Proteus vulgaris were digested with the restriction endonucleases EcoRI and HindIII. After electrophoresis in agarose gels, the fragments were subjected to Southern blot hybridization analysis with a biotin-labeled cDNA probe transcribed from a mixture of 16S and 23S rRNA from P. stuartii NCTC 11800T. The pattern of bands (the rDNA fingerprint), which depended on restriction fragment length polymorphisms containing rRNA genes, was used as a measure of minor genomic variation within and between species. The P. stuartii clinical isolates had similar total digest patterns, but the rDNA fingerprints revealed some heterogeneity between strains, with EcoRI digests providing better strain discrimination than HindIII. Such rDNA fingerprints comprised between five and seven bands with sizes in the range of 5 to 28 kilobases. The 11 different EcoRI patterns were compared by numerical analysis, and several groups or subgroups of strains were identified. Over half (15 of 26) of the urease-negative isolates (subgroups Aa and Ab) had patterns that differed only by the presence or absence of a 25-kilobase band. Urease-negative strains from other clinical material were more heterogeneous in their patterns. No correlation was apparent between strain pattern group and urease production or geographic location of isolate. The P. stuartii rDNA fingerprints were quite distinct from those of allied Providencia and Proteus species and provided a more sensitive measure of minor genomic differences than total DNA digests did.

DNA Probes

cDNA sequence and chromosomal localization of the mouse parvalbumin gene, Pva.

In the homozygous condition, the mutation adr (arrested development of righting response) of the mouse causes a myotonia and a drastic reduction of the Ca2+-binding protein parvalbumin (PV) in fast muscles. Using a rat PV probe, a mouse cDNA clone was isolated from a lambda gt11 wild-type fast-muscle library and its nucleotide sequence was determined. The protein coding and the 3' nontranslated regions of the mouse gene show extensive homology with the rat PV gene. The result of Southern blot hybridization is consistent with a single copy gene for parvalbumin. Restriction fragment length polymorphisms (RFLPs) between Mus musculus domesticus (e.g. C57BL/6) and Mus spretus (SPE) were detected with the enzymes Eco RI, Pst I, and Sst I. The restriction fragment patterns of DNA samples from 65 individual offspring of (C57BL/6 x SPE)F1 x C57BL/6 backcrosses were tested with the PV probe and matched, for linkage detection, to pre-existing patterns established with various RFLP probes on the same samples. A co-distribution of PV-RFLPs with Pvt-1 and Mlvi-2, which had been localized on chromosome 15, was detected. Thus, the structural gene for PV, designated Pva, maps to chromosome 15 of the mouse whereas the adr mutation shows no linkage with markers on this chromosome. Gene locus homology between chromosome 15 of the mouse and chromosome 22 of man (which carries the human PV gene) is discussed.

Amino Acid Sequence

Structure and expression of the human cystatin C gene.

The structural organization of the gene for the human cysteine-proteinase inhibitor cystatin C was studied. Restriction-endonuclease digests of human genomic DNA hybridized with human cystatin C cDNA and genomic probes produced patterns consistent with a single cystatin C gene and, also, the presence of six closely related sequences in the human genome. A 30 kb restriction map covering the genomic region of the cystatin C gene was constructed. The positions of three polymorphic restriction sites, found at examination of digests of genomic DNA from 79 subjects, were localized in the flanking regions of the gene. The gene was cloned and the nucleotide sequence of a 7.3 kb genomic segment was determined, containing the three exons of the cystatin C structural gene as well as 1.0 kb of 5'-flanking and 2.0 kb of 3'-flanking sequences. Northern-blot experiments revealed that the cystatin C gene is expressed in every human tissue examined, including kidney, liver, pancreas, intestine, stomach, antrum, lung and placenta. The highest cystatin C expression was seen in seminal vesicles. The apparently non-tissue-specific expression of this cysteine-proteinase inhibitor gene is discussed with respect to the structure of its 5'-flanking region, which shares several features with those of housekeeping genes.

Amino Acid Sequence

The pattern of expression of the Xenopus laevis tadpole alpha-globin genes and the amino acid sequence of the three major tadpole alpha-globin polypeptides.

We have isolated cDNA clones derived from three tadpole alpha-globin mRNAs of Xenopus laevis. The entire nucleotide sequence of the three mRNAs has been determined from the cDNA clones and is presented together with the deduced amino acid sequence of the encoded polypeptides. Two of the three polypeptide sequences are 96% homologous whilst the third sequence is highly diverged, with only a 72% homology. The three tadpole alpha-globin genes are all similarly diverged from the two X. laevis adult alpha-globin genes with which they display approximately 50% homology. Analysis of several independent clones from each class of tadpole alpha-globin sequence reveals a very high degree of coding region polymorphism for each of the three corresponding genes. Using the cloned DNA sequences as hybridisation probes, we have analysed the expression of the corresponding genes during larval development. We show that all three genes are activated simultaneously early in development and that thereafter all three are expressed at an approximately equivalent level. A fourth tadpole alpha-globin mRNA sequence, for which we do not have a cDNA clone, accumulates co-ordinately with the three major mRNA sequences but to a much lower concentration. This pattern of gene expression differs significantly from that of the tadpole beta-globin genes of X. laevis, despite the two classes of genes being closely linked in the genome.

Amino Acid Sequence

Development and optimization of T-ARMS PCR assays for detection of lethal haplotypes of TADA2A, UR1B, and PORL1B in pigs in Vietnam.

Marker-assisted selection has increasingly relied on single-nucleotide polymorphisms (SNPs) as robust genetic markers, particularly in livestock breeding programs. In pig farming, embryonic mortality significantly affects litter size, and SNPs in reference genes have been implicated as potential causal factors. We developed and optimized a tetra-primer amplification refractory mutation system (T-ARMS) PCR assay for rapid, cost-effective detection of SNPs in 3 candidate genes-TADA2A, PORL1B, URB1-that are associated with embryonic lethality and reproductive performance. Primer sets were designed based on known mutation sites and validated using synthetic gene constructs and porcine genomic DNA from pigs of Duroc and Landrace breeds. Optimization of annealing temperatures and primer concentration ratios yielded distinct and reproducible allele-specific amplicon patterns that were corroborated by PCR-RFLP and Sanger sequencing. Our T-ARMS PCR protocol, which requires minimal equipment and reduces processing time to <3&#x2009;h, had high specificity and efficiency in differentiating wild-type, heterozygous, and homozygous mutant genotypes in 20 Duroc and 20 Landrace pigs. Our Tetra-ARMS PCR assay is a robust and economically viable tool for SNP genotyping in pig breeding programs, potentially contributing to the reduction of embryonic lethality and the improvement of overall reproductive outcomes.

Sus scrofa

Mapping of sequenced genes (700 kbp) in the restriction map of the Escherichia coli chromosome.

This paper describes software (written in Pascal and running on Macintosh computers) allowing localization of unknown DNA fragments from the Escherichia coli chromosome on the restriction map established by Kohara et al. (1987). The program identifies the segment's map position using a restriction pattern analysis obtained with all, or some, of the eight enzymes used by Kohara et al. (1987). Therefore, the sequenced genes available in the EMBL library may be localized on the E. coli chromosome restriction map. This allowed correction of the map (mainly by introducing missing sites in the published maps) at the corresponding positions. Analysis of the data indicates that there is only a very low level of polymorphism, at the nucleotide level, between the E. coli K12 strains used by the various laboratories involved in DNA sequencing. The program is versatile enough to be used with other genomes.

Chromosome Inversion

Turnover of R1 (type I) and R2 (type II) retrotransposable elements in the ribosomal DNA of Drosophila melanogaster.

R1 and R2 are distantly related non-long terminal repeat retrotransposable elements each of which inserts into a specific site in the 28S rRNA genes of most insects. We have analyzed aspects of R1 and R2 abundance and sequence variation in 27 geographical isolates of Drosophila melanogaster. The fraction of 28S rRNA genes containing these elements varied greatly between strains, 17-67% for R1 elements and 2-28% for R2 elements. The total percentage of the rDNA repeats inserted ranged from 32 to 77%. The fraction of the rDNA repeats that contained both of these elements suggested that R1 and R2 exhibit neither an inhibition of nor preference for insertion into a 28S gene already containing the other type of element. Based on the conservation of restriction sites in the elements of all strains, and sequence analysis of individual elements from three strains, nucleotide divergence is very low for R1 and R2 elements within or between strains (less than 0.6%). This sequence uniformity is the expected result of the forces of concerted evolution (unequal crossovers and gene conversion) which act on the rRNA genes themselves. Evidence for the role of retrotransposition in the turnover of R1 and R2 was obtained by using naturally occurring 5' length polymorphisms of the elements as markers for independent transposition events. The pattern of these different length 5' truncations of R1 and R2 was found to be diverse and unique to most strains analyzed. Because recombination can only, with time, amplify or eliminate those length variants already present, the diversity found in each strain suggests that retrotransposition has played a critical role in maintaining these elements in the rDNA repeats of D. melanogaster.

Animals

Whole-genome sequencing reveals divergent and shared selection signatures of heat stress adaptation in indigenous Ethiopian zebu cattle from dry-hot and humid-hot&#xa0;environments.

African zebu cattle (Bos indicus) exhibit remarkable adaptations to extreme thermal conditions, yet the genomic basis of this resilience remains incompletely characterized. Ethiopia provides a unique natural setting in which closely related zebu populations have adapted divergently to dry-hot (DHETZ) and humid-hot (HHETZ) climates. In this study, we reanalyzed publicly available whole-genome sequencing datasets from 46 Ethiopian zebu cattle from five populations and compared them with Asian zebu, Sudanese zebu, African taurine, and European taurine breeds. By integrating genome-wide SNP analysis, population genetic structure assessment, and multiple selection scans (iHS, Hp, XP-EHH, and XP-CLR), we identified distinct and shared selection signatures between DHETZ and HHETZ. We detected 33.7 million and 34.2 million biallelic autosomal SNPs in DHETZ and HHETZ, respectively. Ethiopian zebu clustered closely with Sudanese zebu but showed clear divergence from Asian zebu and taurine breeds. DHETZ and HHETZ exhibited very low genetic differentiation (FST&#x2009;=&#x2009;0.0063), consistent with their shared ancestry; however, each group displayed unique selection signals. In DHETZ, iHS and Hp detected 298 and 113 candidate regions, respectively, whereas in HHETZ, they detected 244 and 138 regions, respectively. Cross-population XP-EHH and XP-CLR analyses identified 163 and 227 divergent regions between DHETZ and HHETZ, respectively. Integration of the four selection scans identified 19 high-confidence candidate regions in DHETZ and 13 in HHETZ. DHETZ showed strong selection in genes involved in oxidative stress regulation, protein folding, mitochondrial function, and vascular remodeling, including SESN2, DNAJC8, GRPEL2, ABLIM3, and AFAP1L1. In contrast, HHETZ displayed signatures in genes associated with immune responses, energy metabolism, and angiogenesis inhibition, including MYD88, PRKACA, PRKACB, and WIF1. Several genes, including VEGFC, TNIP3, and DMXL2, were under selection in both groups, suggesting conserved mechanisms of thermotolerance and reproductive adaptation. The shared VEGFC signal and the HHETZ-specific WIF1 signal may indicate a distinct vascular regulatory mechanism in the dry-hot and humid-hot environments. Our results reveal a dual pattern of genomic adaptation in Ethiopian zebu cattle and provide candidate loci for future validation and climate-resilient livestock breeding.

Animals

Organization, polymorphism, and molecular cytogenetics of chromosome-specific alpha-satellite DNA from the centromere of chromosome 2.

The general usefulness of alpha-satellite DNA probes for the molecular, genetic, and cytogenetic analysis of the human genome is enhanced by their being chromosome specific. Here, we describe the isolation and characterization of an alpha-satellite subset specific for human chromosome 2. Three clones, p2-7, p2-8, and p2-11, obtained from an EcoRI-digested lambda phage library from flow-sorted chromosome 2, are specific for the centromere of chromosome 2 by somatic cell hybrid mapping and chromosomal in situ hybridization. Nucleotide sequence analysis identifies the chromosome 2-specific alpha-satellite subset D2Z1 as a member of the suprachromosomal subfamily II, which is based on a characteristic two-monomer repeat. The D2Z1 subset is further organized as a series of diverged 680-bp tetramers, revealed after digestion of genomic DNA with HaeIII, HindIII, HinfI, StuI, and XbaI. Using pulsed-field gel electrophoresis (PFGE), probes p2-7, p2-8, and p2-11 detect polymorphic restriction patterns within the alpha-satellite array. Among 15 different chromosomes 2 (in two two-generation families and one three-generation family), the length of the D2Z1 alpha-satellite array varied between 1050 and 2900 kb (mean = 1850 kb, SD = 550 kb). The inheritance of the chromosome 2 alpha-satellite arrays and their associated polymorphisms was strictly Mendelian.

Aneuploidy

Genetic Association Between Sleep Traits and Vertigo Risk: A Two-sample Bidirectional Mendelian Randomization Study.

BACKGROUND: Observational studies suggest the potential association between sleep traits and vertigo; however, causal evidence remains limited. OBJECTIVE: This study aimed to explore the relationship between genetically predicted sleep traits and vertigo with the Mendelian randomization (MR) method. METHODS: Instrumental variables for sleep traits (snoring, sleep duration, insomnia, daytime sleepiness, daytime napping, and chronotype) were adopted from genomewide association studies (GWAS) data of European ancestry from UK Biobank. The summary-level datasets of vertigo were retrieved from the GWAS of FinnGen. Inversevariance weighted (IVW) method was adopted as the main analysis. RESULTS: IVW analysis revealed a significant association between genetically predicted daytime napping (OR = 1.51, 95% CI =1.08-2.12, P = 0.016) and chronotype (OR = 1.13, 95% CI =1.01-1.26, P = 0.033), both of which were associated with an increased risk of vertigo. However, we did not find evidence for a causal effect of snoring, overall sleep duration, long sleep duration, short sleep duration, insomnia, and excessive daytime sleepiness on vertigo. No reverse causality was detected. CONCLUSION: Our findings suggest that abnormal sleep patterns may serve as risk factors for vertigo disorders and offer opportunities for the prevention and management of vertigo disorders.

Humans

DNA fingerprinting in horses using a simple (TG)n probe and its application to population comparisons.

A synthetic polynucleotide (TG)n was hybridized to equine DNA digested with HinfI and hypervariable hybridization patterns were obtained. Mendelian inheritance of these DNA fingerprinting patterns was confirmed by pedigree analysis. Estimates of the probabilities of identical band patterns in unrelated individuals of different breeds (Swedish Trotters, North Swedish Trotters, Thoroughbreds and Arabians) were in the range 1 x 10(-4) - 7 x 10(-6). The variability derived with the (TG)n probe in horses was higher than what we obtained with several other commonly used probes for DNA fingerprinting. Individuals within breeds tended to be more similar to each other with regard to DNA fingerprint pattern than to individuals of other breeds. Moreover, a parsimony analysis made on the basis of the hybridization patterns gave clustering of individuals within breeds. The possibility of using hypervariable probes for the identification of breed-specific characters is discussed.

Animals