Courtship Bout Duration in per Circadian Period Mutants In Drosophila melanogaster

Mutations on the period locus of Drosophila melanogaster influence circadian periods as well as the rhythm in inter-pulse intervals in male courtship song; per ^L mutations produce long circadian periods and courtship song rhythms and per ^s mutations produce short circadian periods and courtship song rhythms. Thus, these mutations influence timing mechanisms over both long and short behavioral time horizons. We examined if the mean courtship duration of male Drosophila melanogaster cycles rhythmically, and if mutations at the period locus influence courtship bout duration. We measured the courtship bout durations of the following: (1) wild type Canton-S (per ⁺) males; (2) per ^L males; and (3)per ^s males. Rhythmicity of courtship bout duration could not be mathematically determined. Mean courtship bout duration did not differ among the three groups; thus, mutations at the period locus did not influence mean courtship duration. There was a nonsignificant trend for per ⁺ males that were successful at mating to have longer mean courtship duration than unsuccessful males.     

A novel deletion mutation in CENPJ gene in a Pakistani family with autosomal recessive primary microcephaly

Autosomal recessive primary microcephaly (MCPH) is a rare human genetic disorder in which the head circumference is reduced because of abnormality in fetal brain growth. To date, six loci and four genes have been identified for this condition. Our study of primary MCPH led to the identification of 33 Pakistani families with different ethnic backgrounds. Most of these families showed linkage to MCPH5 locus on chromosome 1q31. Only one family with Pashtoon origin from a remote region in Pakistan linked to MCPH6 locus on chromosome 13q12.12–q12.13. Sequence analysis of exon 11 of CENPJ gene, located at MCPH6 locus, revealed a novel four base pair deletion mutation, which is predicted to be protein truncating.     

Chloroplast gene transmission in Chlamydomonas reinhardtii. A model for its control by the mating-type locus

Summary In sexual crosses of Chlamydomonas reinhardtii, genes residing in the chloroplast (cp) are most often transmitted from the mating-type plus (mt ⁺) parent only. Galloway and Goodenough (1985) proposed a model in which the mt locus (linkage group VI) is a complex region containing several genes involved in the control of both gametic differentiation and cp inheritance. The mt ⁺ locus contains: the sfu locus necessary for sexual fusion between gametes; the upp locus (uniparental plus) which controls cp gene inheritance and also perhaps zygote maturation; and the sad locus which functions in sexual adhesion. The mt ^– locus also contains a sad locus as well as a regulatory element (mid) necessary for the minus dominance in mt ⁺/mt ^– diploid gametes. This model has been extended to include new genetic functions linked to the mt ⁺ or mt ^– locus. In this new system, there is a group of genes (maps for mating-type plus structure), present in both plus and minus strains, controlling some mt ⁺ phenotypical traits as well as the synthesis of an activator of the cp DNA nuclease; two genes contained in the mt ^– locus — one (cge for cp genomic elimination) coding for a nuclease (in an inactive form) located in the chloroplast and another (mid) coding for a repressor of maps; one gene (upp) contained in the mt ⁺ locus, coding for a substance preventing the synthesis or the activity of the nuclease and perhaps also acting on the maps product. The model can be applied to explain the complex dominance/ recessivity relationships observed between the mt ⁺ and mt ^– alleles in heterozygous diploid gametes, the basis for mitotic vs meiotic zygote formation and the differences in transmission observed for these two physiologically distinct zygote classes. Application of the model for prediction of mutant phenotypes and the design of future experiments is also described.     

Gene deletion and allelic replacement in the filamentous fungus <Emphasis Type="Italic">Podospora anserina</Emphasis>

Gene replacement via homologous recombination is a fundamental tool for the analysis of gene function. However, this event is rare in organisms like the filamentous fungus Podospora anserina. We show here that deletion of the PaKu70 gene is an efficient strategy for improving gene manipulation in this organism. By using the ΔPaKu70 strain, it is now possible (1) to produce deletion mutants with an efficiency of 100%, (2) to achieve allelic exchange by introducing a mutated allele associated with a selection cassette at the locus, (3) to introduce a mutation in a gene without co-insertion of a selectable marker and without any modification of the target locus.     

DFNB66 and DFNB67 loci are non allelic and rarely contribute to autosomal recessive nonsyndromic hearing loss

We previously mapped the DFNB66 locus to an interval overlapping the DFNB67 region. Mutations in the LHFPL5 gene were identified as a cause of DFNB67 hearing loss (HL). However, screening of the coding exons of LHFPL5 did not reveal any mutation in the DFNB66 family. The objective of this study was to check whether DFNB66 and DFNB67 are distinctive loci and determining their contribution to HL. In the DFNB66 family, sequencing showed absence of mutations in the untranslated regions and the predicted promoter sequence of LHFPL5. Analysis of five microsatellites in the 6p21.31–22.3 region and screening of the LHFPL5 gene by DNA heteroduplex analysis in DHPLC revealed a novel mutation (c.89dup) in one out of 129 unrelated Tunisian families with autosomal recessive nonsyndromic (ARNS) HL. Our findings suggest that two distinct genes are responsible for DFNB66 and DFNB67 HL. These loci are likely to be a rare cause of ARNSHL.     

Influence of coat color genes on seizure behavior in Mongolian gerbils

Seizure tendencies of three separate lines of Mongolian gerbilsMeriones unguiculatus carrying three different coat color alleles were investigated. These alleles were agouti (A/–), black or nonagouti (a/a), or sandy (pink-eyed dilutionp/p). Each animal was stroked on the back and then placed in a novel cage for 5 min while its seizure activity was measured in terms of latency, duration, and severity (grade). The results indicate that gerbils which are homozygous recessive at thepink-eyed dilution locus (sandy) exhibit less severe and shorter seizures than others. However, gerbils which are homozygous recessive at theagouti gene locus (black) show a shorter latency to manifest seizures than the other animals. These results indicate that the genetic mechanism determining coat color in Mongolian gerbils may also influence the susceptibility of these animals to seizure arising from novel stimulation.This research was supported by a grant from the NSERC of Canada to Roderick Wong.     

Potassium and sodium ions in the nerve tissue of emotionally overstrained rabbits

Measurement of K⁺ and Na⁺ concentrations in samples of individual brain nuclei and in ganglia of the autonomic nervous system from rabbits subjected to severe emotional stress (ES) through aperiodic stimulation of ventromedial hypothalamic nuclei and electrocutaneous stimulation revealed significantly altered levels of these ions in locus ceruleus samples from animals predisposed to ES-induced cardiovascular disorders and in samples of neurons of the caudal part of the brainstem from those resistant to such disorders. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, No 8, pp. 129–131, August, 1994 Presented by K. V. Sudakov, Member of the Russian Academy of Medical Sciences     

A PCR-based integrated protocol for the structural analysis of the 13th exon of the human beta-myosin heavy chain gene (MYH7): development of a diagnostic tool for HCM disease

Familial Hypertrophic Cardiomyopathy (FHC) constitutes a genetic disease of the sarcomere characterized by a Mendelian pattern of inheritance. A variety of different mutations affecting the at least eight sarcomeric gene products has been identified and the majority of them appear to function through a dominant negative mechanism. Family history analysis and genetic counseling have been widely adopted as integral tools for the evaluation and management of individuals with Hypertrophic Cardiomyopathy (HCM). Genetic testing of the disease has been progressively released into the clinical mainstream, thus rendering the development of novel and potent molecular diagnostic protocols an inevitable task. To this direction, we have evolved an integrated PCR-based molecular protocol, which through the utilization of novel “exonic” primers allows, among others, the structural analysis of the 13th exon of the human β-myosin heavy chain gene locus (MYH7) mainly characterized by the critical for HCM Arginine residue 403 (R⁴⁰³). Interestingly, through a DNA sequencing approach, a single nucleotide substitution from “G” to “T” was detected in the adjacent 13th intron, thus divulging the versatile potential of the present molecular protocol to clinical practice.     

Targeting of the actin cytoskeleton during infection by Salmonella strains

Many bacterial pathogens produce virulence factors that alter the host cell cytoskeleton to promote infection. Salmonella strains target cellular actin in a carefully orchestrated series of interactions that promote bacterial uptake into host cells and the subsequent proliferation and intercellular spread of the organisms. The Salmonella Pathogenicity Island 1 (SPI1) locus encodes a type III protein secretion system (TTSS) that translocates effector proteins into epithelial cells to promote bacterial invasion through actin cytoskeletal rearrangements. SPI1 effectors interact directly with actin and also alter the cytoskeleton through activation of the regulatory proteins, Cdc42 and Rac, to produce membrane ruffles that engulf the bacteria. SPI1 also restores normal cellular actin dynamics through the action of another effector, SptP. A second TTSS, Salmonella Pathogenecity Island 2 (SPI2), translocates effectors that promote intracellular survival and growth, accompanied by focal actin polymerization around the Salmonella-containing vacuole (SCV). A number of Salmonella strains also carry the spv virulence locus, encoding an ADP-ribosyl transferase, the SpvB protein, which acts later during intracellular infection to depolymerize the actin cytoskeleton. SpvB produces a cytotoxic effect on infected host cells leading to apoptosis. The SpvB effect appears to promote intracellular infection and may facilitate cell-to-cell spread of the organism, thereby enhancing virulence.     

SNPs in the KCNJ11-ABCC8 gene locus are associated with type 2 diabetes and blood pressure levels in the Japanese population

Many genetic association studies support a contribution of genetic variants in the KCNJ11-ABCC8 gene locus to type 2 diabetes (T2D) susceptibility in Caucasians. In non-Caucasian populations, however, there have been only a few association studies, and discordant results were obtained. Herein, we selected a total of 31 SNPs covering a 211.3-kb region of the KCNJ11-ABCC8 locus, characterized the patterns of linkage disequilibrium (LD) and haplotype structure, and performed a case-control association study in a Japanese population consisting of 909 T2D patients and 893 control subjects. We found significant associations between eight SNPs, including the KCNJ11 E23K and ABCC8 S1369A variants, and T2D. These disease-associated SNPs were genetically indistinguishable because of the presence of strong LD, as found previously in Caucasians. For the KCNJ11 E23K variant, the most significant association was obtained under a dominant genetic model (OR 1.32, 95% CI 1.09–1.60, P = 0.004). A meta-analysis of East Asian studies, comprising a total of 3,357 T2D patients (77.4% Japanese) and 2,836 control subjects (77.8% Japanese), confirmed the significant role of the KCNJ11 E23K variant in T2D susceptibility. Furthermore, we found evidence suggesting that the KCNJ11 E23K genotype is independently associated with higher blood-pressure levels. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Sequencing and Characterisation of p74 Gene in Two Isolates of Anticarsia Gemmatalis MNPV

P74 is a protein encoded in the genome of baculoviruses, associated with the envelopes of occluded virus. Its presence proved to be essential for per os infection. In first place, in this work we designed two universal primers to amplify a sequence region of the p74 ORF in baculoviruses from different classification groups. Then, by the use of these amplicons we obtained the complete sequence of the p74 locus from two isolates of AgMNPV, 2D (Brazil) and SF (Argentina). In the flanking regions we determined the complete sequence of p10 gene and a portion of p26 gene. Comparing both p74 sequence data (ORFs of 1935 bp) we found fifteen nucleotide changes that result in six amino acid changes. Comparisons of AgMNPV p74s with other baculovirus homologous genes indicate a close relationship with other group I Nucleopolyhedrovirus, in particular CfDEFNPV. These results were based on ORF sequence, amino acid sequence and gene order. The predictive studies about secondary structure and hydrophobic index point at six regions potentially associated to its function or native conformation. Finally, the detection of p74 mRNA after virus DNA replication confirms a late expression pattern.     

Association analysis of HSP90B1 with bipolar disorder

Pathophysiological role of endoplasmic reticulum (ER) stress response signaling has been suggested for bipolar disorder. The goal of this study was to test the genetic association between bipolar disorder and an ER chaperone gene, HSP90B1 (GRP94/gp96), which is located on a candidate locus, 12q23.3. We tested the genetic association between bipolar disorder and HSP90B1 by case-control studies in two independent Japanese sample sets and by a transmission disequilibrium test (TDT) in NIMH Genetics initiative bipolar trio samples (NIMH trios). We also performed gene expression analysis of HSP90B1 in lymphoblastoid cells. Among the 11 SNPs tested, rs17034977 showed significant association in both Japanese sample sets. The frequency of the SNP was lower in NIMH samples than in Japanese samples and there was no significant association in NIMH trios. Gene expression analysis of HSP90B1 in lymphoblastoid cells suggested a possible relationship between the associated SNP and mRNA levels. HSP90B1 may have a pathophysiological role in bipolar disorder in the Japanese population, though further study will be needed to understand the underlying functional mechanisms.     

Stability of minisatellite loci in the genome of cultured hela cells

The stability of minisatellite loci representing DNA with the tandem organization of repeats is studied. DNA profiles of 194 HeLa clones are identical to the parent culture. They exhibit 36 bands detectable by the minisatellite probe Red4. Since the method ensures the record of changes in minisatellite loci appearing during the first two divisions of parent cell, mutations are assessed in 27,936 locus tests. Hence, the incidence of mutations in the culture is not higher than 3.5×10⁻⁷ per locus/per mitosis, providing that the number of generations in parental homogenous culture is taken into account. Translated fromByulleten' Eksperimetal'noi Biologii i Meditsiny, Vol. 122, No. 9, pp. 311–313, September, 1996     

Characterization of AcMNPV with a deletion of me53 gene

The Autographa Californica multiple nucleopolyhedrovirus (AcMNPV) me53 gene, which was previously reported as one of the major early-transcribed genes, was deleted through homologous recombination from an AcMNPV genome propagated as a bacmid DNA in E. coli, generating a me53 gene knockout bacmid. Green fluorescent protein (GFP) expression analysis and supernatant passage assay revealed that the me53 knockout bacmid was unable to replicate in cell culture, while me53 repair bacmid, which was generated by reinsertion of the me53 gene into the mutant at a different locus (the gentamicin locus) with ET-recombination technique, resumed viral replication ability at wild-type levels, indicating that the defective phenotype of the me53 knockout virus was directly due to the deletion of the me53-ORF. Subsequent electron microscopy revealed that the me53 knockout bacmid failed to form nucleocapsid in the nuclei of the transfected cells, though viral infection seemed to be initiated. Meanwhile, real-time PCR analysis based on SYBR Green fluorescence indicated abolishment of the viral DNA replication by me53 gene inactivation. Thus, it is demonstrated for the first time that me53 knockout blocked viral DNA replication, nucleocapsid formation, and consequent BV and ODV production.     

The orientation of gene maps by recombination of flanking markers for the am locus of Neurospora crassa

Fincham (1967), Smyth (1973b) and Rambosek and Kinsey (1983) have each generated fine-structure maps of the am gene of Neurospora crassa. Each map had a consistent linear order of alleles but the assignment of an orientation with respect to other linkage group-V loci differed. Fincham found the end marked by the am ₆ allele to be at the distal end of the locus, Smyth found am ₆ to be at the proximal end while the data of Rambosek and Kinsey did not suggest an orientation. Smyth's orientation has been adopted as the standard, but not unreservedly. We have aligned the genetic and physical maps of the am gene, showing that am ₆ is at the distal end, supporting Fincham's orientation. However, we suggest that an assumption used to orient fine structure genetic maps is flawed and that the conflicting orientation between these three studies follows from the different choice of flanking markers.     

Organization and structure of plastome psbF,psbL, petG and ORF712 genes in Chlamydomonas reinhardtii

Summary We have determined the nucleotide sequence of a 5159 base-pair (bp) region of the Chlamydomonas reinhardtii plastome containing three photoelectron transport genes, psbF, psbL and petG, and an unusual open reading frame, ORF712. The photosynthetic genes have an unprecedented arrangement. psbF and psbL are located in close proximity to petG, and are not grouped with two other genes of the cytochrome b₅₅₉ locus, psbE and ORF42. ORF712, located adjacent to psbL, has homology at its 5-and 3-ends to the ribosomal protein rps3 gene, but contains, a central 437 residue domain that lacks similarity to any other known sequence. These sequences add to the growing body of evidence that the chloroplast genome of C. reinhardtii has a significantly different gene arrangement to its counterpart in plants. The structure of ORF712 also provides another example of a phenomenon we have discovered with C. reinhardtii RNA polymerase genes (Fong and Surzycki 1992); namely, that the algal plastome contains chimeric genes in which reading frames with homology to known genes are juxtaposed in-frame with long coding regions of unknown identity.     

Resistance to cadmium is under the control of the CAD2 gene in the yeast Saccharomyces cerevisiae

Summary A cadmium-resistant strain, X3382-3A, which is able to grow in a medium containing 0.2 mM cadmium sulfate, was picked out from our laboratory stock strains of Saccharomyces cerevisiae. The cadmium resistance of this strain is controlled by a single dominant nuclear gene, denoted as CAD2. The locus of CAD2 was mapped by gene linkage to a site 15.5 centimorgans to the right of the his7 locus on the right arm of chromosome II. The cadmium resistance of the strain carrying CAD2 was evaluated for its properties of cadmium uptake, cadmium distribution and cadmium-metallothionein formation, in comparison with those of some other strains. The results suggest that the novel type of cadmium resistance controlled by CAD2 does not involve production of a cadmiumm-metallothionein.     

Are Vertical Behaviour Patterns Related to the Pantophysin Locus in the Atlantic Cod (<Emphasis Type="Italic">Gadus morhua</Emphasis> L.)?

Throughout their geographic distribution, marine fish species often form subpopulations with limited connectivity, among which individuals display a variety of migratory behaviours. Fish behaviour experiments using Data Storage Tags (DSTs) have been useful to define the natural movement of individuals. In Icelandic waters, such experiments have indicated the presence of two distinct behaviour types of the Atlantic cod Gadus morhua, related to vertical migrations and habitat choice in feeding migrations. Some individuals have been shown to stay most of the time in shallow waters characterised by the seasonal trend in temperature for the shelf waters, while other migrate to deeper and colder waters where most of them forage in temperature fronts characterized by highly variable temperatures. The analysis of the pantophysin locus (Pan I) of the same individuals revealed that individuals carrying the Pan I^AA genotype are likely to display a shallow water feeding migrations while individuals carrying the Pan I^BB genotype preferred deeper waters and forage near thermal fronts. The heterozygote exhibited both type of behaviours. This study therefore suggests that further research need to be done on the pantophysin locus and its potential effects on cod phenotypes to assess the potential relationship between this locus and the behavioural types described. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Edited by Stephen Maxson.     

A test for rare male mating advantage at an “enzyme locus” inDrosophila

Matings betweenDrosophila pseudoobscura strains differeing at the amylase (Amy) locus were observed in Elens-Wattiaux chambers. Males homozygous for eitherAmy ^1.00 orAmy ^0.84 alleles in the CH gene arrangement enjoyed a mating advantage when moderately rare, but none when quite rare. The minority male advantage for strains differing at theAmy locus, and other loci linked to it, was comparable in size to that observed between strains carrying the ST or CH gene arrangements, and either alike or different at theAmy locus. Although some features of our results are puzzling, there is evidence that theAmy locus and others for which it serves as a marker have effects on mating behavior which include some degree of rare male mating advantage.