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PubMed1983

Implantation of transformant strains of the bacterium Streptococcus sanguis into adult human mouths.

Streptococcus sanguis strains isolated from dental plaque of 12 subjects were screened for their ability to undergo genetic transformation using a streptomycin-resistance marker. All subjects harboured at least one transformable strain. Eight of the subjects were implanted with transformant strains originally isolated from their own mouth, whereas four subjects received bacteria from other donors. The Strep. sanguis transformants became successfully implanted; their oral levels remained virtually unchanged during the 3-month experimental period. Their oral establishment did not seem to be related to whether the subjects were implanted with their own transformant strains or not. The implanted Strep. sanguis could be recovered both from teeth, oral soft tissues and throat.

Adult↗
PubMed2002

Quantitative high throughput endothelial cell migration and invasion assay system.

We have developed a novel assay system combining fluorescent signal-blocking microporous PET membrane inserts and ECM to study dynamic endothelial cell migration and invasion. The assay described here may be applicable to other cell types for analogous assay. The currently used method for analyzing migration and invasion requires the removal of nonmigratory cells from the top of a clear microporous membrane. This laborious step is required to quantitate the invaded or migrated cells on the bottom of the membrane. When the fluorescent signal blocking the microporous membrane is used, the fluorescent signal from noninvaded or nonmigratory cells from the top of the membrane is virtually eliminated and allows for rapid and efficient measurement of the migrated or invaded cells on the underside of the insert. Unlike conventional low throughput migration assays, this assay is easy to perform and provides a quantitative invasion/migration profile of the chemoattractant of choice. This robust automation compatible assay will serve as a powerful tool to screen potential antiangiogenic compounds for drug discovery.

3T3 Cells↗
PubMed2000

A disposable amperometric sensor screen printed on a nitrocellulose strip: a glucose biosensor employing lead oxide as an interference-removing agent.

A new type of disposable amperometric sensor is devised by screen printing thick-film electrodes directly on a porous nitrocellulose (NC) strip. The chromatographic NC strip is then utilized to introduce various sample pretreatment layers. As a preliminary application, a glucose biosensor based on hydrogen peroxide detection is constructed by immobilizing glucose oxidase (GOx) on the NC electrode strip and by formulating a strong oxidation layer (i.e., PbO2) at the sample loading area, placed below the GOx reaction band. The screen-printed PbO2 paste serves as a sample pretreatment layer that removes interference by its strong oxidizing ability. Samples applied are carried chromatographically, via the PbO2 paste, to the GOx layer, and glucose is catalyzed to liberate hydrogen peroxide, which is then detected at the electrode surface. The proposed NC/PbO2 strip sensor is shown to be virtually insusceptible to interfering species such as acetaminophen and ascorbic and uric acids and to exhibit good performance, in terms of the sensor-to-sensor reproducibility (standard deviation, +/-0.026 - +/-0.086 microA), the sensitivity (slope, -0.183 microA/mM), and the linearity (correlation coefficient, 0.994 in the range of 0-10 mM).

Biosensing Techniques↗
PubMed2004

Provision of Epstein-Barr virus-transformed B-cell lines in a routine tissue typing laboratory: practicalities and applications.

A bank of Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell lines (BCLs) has been established in this laboratory over the last 7 years. Novel, rare and unusual HLA phenotypes were highlighted during routine clinical testing and during typing of volunteer haematopoietic stem cell donors for the Welsh Bone Marrow Donor Registry. The BCLs are routinely used as laboratory reagents, as a source of DNA for reference purposes and for research work. Consenting donors are tested for hepatitis B surface antigens (HBsAg), human immunodeficiency virus (HIV) and hepatitis C virus (HCV) before their B-lymphocytes are transformed. Strict bio-identity checks are performed before and after transformation and after each BCL expansion. Each BCL is tested regularly for mycoplasma contamination. A total of 230 blood samples were transformed. One hundred and fifty-nine sterile samples produced 157 BCLs (98.7% success), while 71 non-sterile samples produced 50 BCLs (70.4% success), giving an overall success rate of 90.0%. Fifteen of the transformation failures have since been repeated successfully. Factors contributing to the high success rate and reasons for the 23 failed transformations are discussed. The successful development and use of pools of BCLs for HLA antibody screening by flow cytometry are described. Whilst certain training and health and safety issues require close attention, it is clear that EBV transformation of B lymphocytes and/or the use of BCLs is feasible in a routine tissue typing laboratory and that BCLs are a valuable resource. Careful adherence to the methods and procedures detailed here should virtually guarantee successful transformation (98.7%) from good quality, sterile whole blood samples.

B-Lymphocytes↗
PubMed1994

Effects of feed additives and veterinary drugs on aldosterone production and release by porcine adrenal cells in vitro.

The preparation of suspensions of porcine adrenocortical cells is described. Within the conditions adopted, the cell suspension responded to various agents as expected. It was possible to screen drugs (standard range 0.3-100 microM, incubation period 1 h) for actions on the production/release of aldosterone by the cortical cells using 1 microM deoxycorticosterone as substrate. Progesterone, pregnenolone or corticosterone were also used as substrates. Feed additives of the quinoxaline type induced a slowly developing inhibition of aldosterone production/release by the cell suspension, which was virtually irreversible. During the standard 1 h incubation period inhibitions of up to 22 +/- 2% of control were observed, which increased upon prolongation of the incubation by 2 h. With 100 microM cyadox the inhibition increased from 19 +/- 2% to 35 +/- 2% with prolonged incubation. Ten nitrofuran compounds exerted a more rapidly developing inhibition (by up to 79 +/- 1% of control) of aldosterone production/release, which was reversible. A submaximal inhibition with 10 microM furazolidone of 21 +/- 5% increased to 40 +/- 1% with longer incubation. The concentrations at which these compounds exerted this effect in vitro were well below the peak blood plasma concentrations encountered after administration of the drugs in therapeutic doses. Polyether-antibacterials/ionophores rapidly inhibited aldosterone production/release (to 26 +/- 1% of control) and this effect was completely reversible. The nitroimidazole compounds tested did not affect aldosterone production/release when deoxycorticosterone or progesterone were used as substrates. With use of corticosterone and to a lesser extent with pregnenolone as substrates a clear inhibition (to 73 +/- 3% of control) of aldosterone production was obtained. Amprolium in concentrations up to 100 microM, with deoxycorticosterone as substrate, did not induce a significant change in aldosterone production/release by the suspension of adrenocortical cells. In the same dose range tylosin and roxarsone induced a small but significant inhibition (by up to 10 +/- 3% of control) of aldosterone production/release, which was not dose-dependent. It is concluded that a wide range of growth-promoting drugs may be able to change aldosterone production/release in the animal.

Adrenal Cortex↗
PubMed1994

Informativity of intragenic microsatellites for carrier detection and prenatal diagnosis of cystic fibrosis in the Italian population.

Molecular diagnosis of cystic fibrosis (CF) in the Italian population, based on the detection of the deltaF508 mutation (51.2% of CF chromosomes), provides full informativity for prenatal diagnosis (PDN) in about 28% of families at risk. Identification of the predominant non-deltaF508 mutations allows the characterization of about 70% of CF chromosomes, making approximately 48% of couples fully informative. In families where at least one chromosome remains uncharacterized, allele segregation is still determined using RFLPs closely linked to the CF gene. The recent identification of three polymorphic clusters of dinucleotide repeats (IVS8/GT, IVS17b/TA and IVS17b/CA) led us to evaluate whether their analysis might improve feasibility studies for prenatal diagnosis or heterozygote identification. One hundred nuclear families with a CF child, reflecting the general Italian deltaF508 mutation distribution, were genotyped for the three microsatellites. In this study microsatellite analysis using IVS8/GT and IVS17b/TA allowed the identification of both parental CF chromosomes in 94% of couples; inclusion in the study of the less polymorphic repeat locus, IVS17b/CA, slightly improved this percentage (97%). Hence, a strategy involving primarily the detection of the deltaF508 mutation and secondarily microsatellite analysis makes possible PDN of CF in virtually all Italian CF families.

Base Sequence↗
PubMed1996

Imaging characteristics of x-ray capillary optics in digital mammography.

Computed radiography (CR) has shown promise in digital mammographic screening due to its good low spatial frequency MTF and its relatively wide exposure latitude. The CR image format has not gained acceptance clinically because of reduced high spatial frequency resolution as compared to film-screen images. X-ray capillary optics, aligned between the breast and CR phosphor imaging plate, will capture primary x-ray photons almost exclusively. Due to the very small angle of acceptance, scattered photons angled more than about 1.6 x 10(-3) radians from primary trajectory will not be accepted at the capillary optic entrance. The virtual elimination of detected scatter means almost 100% of the possible primary contrast should be visible in the image. In addition, the image can be magnified without focal spot blurring. Effective resolution of CR images can be increased by a factor equal to that magnification. Clinical implementation of future capillary optics are expected to be either in the form of a large, stationary, post-patient optic that accepts primary from the entire breast or a fan-shaped optic that is scanned across the breast. Measurements of a test capillary optic showed a reduction of scatter fraction to 0.018. Images of a lucite contrast detail phantom revealed a corresponding increase in image contrast when compared to anti-scatter grid and no grid methods. Spectral transmission measurements using a high-purity germanium detector showed good primary transmission (45%-50%) in the mammographic energy range. The MTF measurements of both stationary and scanned capillary optics showed improvement at the 5% MTF level to 8.4 mm-1 for scanned optics and 9.2 mm-1 for stationary optics representing a 68% and 84% respective increase over the CR MTF without magnification or capillary optics.

Capillary Action↗
PubMed2006

Transposon-assisted cloning and traceless mutagenesis of adenoviruses: Development of a novel vector based on species D.

Until recently, adenovirus (Ad)-mediated gene therapy was almost exclusively based on human Ad type 5 (Ad5). Preexisting immunity and the limited, coxsackievirus and adenovirus receptor-dependent tropism of Ad5 stimulated attempts to exploit the natural diversity in tropism of the other 50 known human Ad serotypes. Aiming in particular at immunotherapy and vaccination, we have screened representative serotypes from different Ad species for their ability to infect dendritic cells. Ad19a, an Ad from species D, was selected for development as a new vector for vaccination and cancer gene therapy. To clone and manipulate its genome, we have developed a novel methodology, coined "exposon mutagenesis," that allows the rapid and precise introduction of virtually any genetic alteration (deletions, point mutations, or insertions) into recombinant Ad bacterial artificial chromosomes. The versatility of the system was exemplified by deleting the E3 region of Ad19a, by specifically knocking out expression of a species-specific E3 gene, E3/49K, and by reinserting E3/49K into an E3 null Ad19a mutant. The technology requires only limited sequence information and is applicable to other Ad species. Therefore, it should be extremely valuable for the analysis of gene functions from any Ad species. In addition, a basic, replication-defective E1- and E3-deleted Ad19a vector expressing GFP (Ad19aGFP) was generated. This new vector based on species D Ads exhibits a very promising tropism for lymphoid and muscle cells and shows great potential as an alternative vector for transduction of cell types that are resistant to or only poorly transduced by conventional Ad5-based vectors.

Adenoviridae↗
PubMed2000

Plasticity and steric strain in a parallel beta-helix: rational mutations in the P22 tailspike protein.

By means of genetic screens, a great number of mutations that affect the folding and stability of the tailspike protein from Salmonella phage P22 have been identified. Temperature-sensitive folding (tsf) mutations decrease folding yields at high temperature, but hardly affect thermal stability of the native trimeric structure when assembled at low temperature. Global suppressor (su) mutations mitigate this phenotype. Virtually all of these mutations are located in the central domain of tailspike, a large parallel beta-helix. We modified tailspike by rational single amino acid replacements at three sites in order to investigate the influence of mutations of two types: (1) mutations expected to cause a tsf phenotype by increasing the side-chain volume of a core residue, and (2) mutations in a similar structural context as two of the four known su mutations, which have been suggested to stabilize folding intermediates and the native structure by the release of backbone strain, an effect well known for residues that are primarily evolved for function and not for stability or folding of the protein. Analysis of folding yields, refolding kinetics and thermal denaturation kinetics in vitro show that the tsf phenotype can indeed be produced rationally by increasing the volume of side chains in the beta-helix core. The high-resolution crystal structure of mutant T326F proves that structural rearrangements only take place in the remarkably plastic lumen of the beta-helix, leaving the arrangement of the hydrogen-bonded backbone and thus the surface of the protein unaffected. This supports the notion that changes in the stability of an intermediate, in which the beta-helix domain is largely formed, are the essential mechanism by which tsf mutations affect tailspike folding. A rational design of su mutants, on the other hand, appears to be more difficult. The exchange of two residues in the active site expected to lead to a drastic release of steric strain neither enhanced the folding properties nor the stability of tailspike. Apparently, side-chain interactions in these cases overcompensate for backbone strain, illustrating the extreme optimization of the tailspike protein for conformational stability. The result exemplifies the view arising from the statistical analysis of the distribution of backbone dihedral angles in known three-dimensional protein structures that the adoption of straight phi/psi angles other than the most favorable ones is often caused by side-chain interactions. Proteins 2000;39:89-101.

Bacteriophage P22↗
PubMed2003

Enhanced spontaneous activity of the mu opioid receptor by cysteine mutations: characterization of a tool for inverse agonist screening.

BACKGROUND: The concept of spontaneous- or constitutive-activity has become widely accepted and verified for numerous G protein-coupled receptors and this ligand-independent activity is also acknowledged to play a role in some pathologies. Constitutive activity has been reported for the mu opioid receptor. In some cases the increase in receptor basal activity was induced by chronic morphine administration suggesting that constitutive activity may contribute to the development of drug tolerance and dependence. Constitutively active mutants represent excellent tools for gathering information about the mechanisms of receptor activation and the possible physiological relevance of spontaneous receptor activity. The high basal level of activity of these mutants also allows for easier identification of inverse agonists, defined as ligands able to suppress spontaneous receptor activity, and leads to a better comprehension of their modulatory effects as well as possible in vivo use. RESULTS: Cysteines 348 and 353 of the human mu opioid receptor (hMOR) were mutated into alanines and Ala348,353 hMOR was stably expressed in HEK 293 cells. [35S] GTPgammaS binding experiments revealed that Ala348,353 hMOR basal activity was significantly higher when compared to hMOR, suggesting that the mutant receptor is constitutively active. [35S] GTPgammaS binding was decreased by cyprodime or CTOP indicating that both ligands have inverse agonist properties. All tested agonists exhibited binding affinities higher for Ala348,353 hMOR than for hMOR, with the exception of endogenous opioid peptides. Antagonist affinity remained virtually unchanged except for CTOP and cyprodime that bound the double mutant with higher affinities. The agonists DAMGO and morphine showed enhanced potency for the Ala348,353 hMOR receptor in [35S] GTPgammaS experiments. Finally, pretreatment with the antagonists naloxone, cyprodime or CTOP significantly increased Ala348,353 hMOR expression. CONCLUSION: Taken together our data indicate that the double C348/353A mutation results in a constitutively active conformation of hMOR that is still activated by agonists. This is the first report of a stable CAM of hMOR with the potential to screen for inverse agonists.

Alanine↗
PubMed1997

Cardiotrophin-1 and the role of gp130-dependent signaling pathways in cardiac growth and development.

The reactivation of an embryonic pattern of gene expression is a central feature common to virtually all forms of cardiac hypertrophy. Unraveling the regulatory mechanisms, growth factors and cytokines controlling gene expression and cell fate during cardiac development may therefore have implications for our understanding of cardiac hypertrophy in the adult. Along this line, a cDNA expression library was established from an embryonic stem cell-based in vitro model of cardiogenesis, and screened for clones that would induce an increase in cell size in cultured cardiomyocytes. This experimental strategy resulted in the isolation of a novel cytokine, cardiotrophin-1 (CT-1), that activates several features of cardiomyocyte hypertrophy in vitro, including sarcomeric organization and embryonic gene expression. CT-1 displays structural similarities to the interleukin (IL)-6 related cytokines. Furthermore, receptor binding studies and functional studies reveal that CT-1 shares the signal transducing receptor components gp130 and LIFR with the previously identified members of the IL-6 cytokine family. CT-1 rapidly activates gp130 and LIFR tyrosine phosphorylation in cultured cardiac myocytes. The growth promoting effects of CT-1 therefore indicate that signaling pathways emanating from gp130 and LIFR are coupled to cardiomyocyte hypertrophy. In support of this notion, the simultaneous overexpression of IL-6 and the IL-6 receptor in transgenic mice has been shown to result in a constitutive tyrosine phosphorylation of gp130 in the myocardium and cardiac hypertrophy. The striking phenotype of gp130 null-mutant mice, generated by homologous recombination, implies gp130 in cardiac development as well: mutant mice exhibit severe ventricular hypoplasia, suggesting a role for gp130-dependent signaling pathways in the expansion of the compact layer of the ventricular myocardium. CT-1 is expressed at high levels in the myocardium during the course of cardiogenesis, and promotes the proliferation and survival of embryonic cardiomyocytes. CT-1 may therefore represent a candidate cytokine to activate gp130 during cardiac development. In summary, cytokines signaling through gp130 are emerging as potent regulators of embryonic heart development and adult cardiac hypertrophy.

Animals↗
PubMed2003

Virtual colonoscopy: past, present, and future.

Virtual colonoscopy is developing into a practical clinical technique. The issues of the steep learning curve and accuracy of the technique are undergoing advances related to patient preparation, scanning technique, reading methods, and CAD. It is probably the best test for patients with an incomplete colonoscopy or for those patients who cannot undergo colonoscopy. Its precise role in screening average-risk patients for colon cancer remains to be defined by ongoing research and clinical trials.

Colonography, Computed Tomographic↗
PubMed2000

Active imagination and the analysis of film.

The emotions aroused by the pleasure-generating mechanisms of the cinema are usually benign because they refer to a virtual world. Experiencing affects aroused by fictions can resemble being drawn into a rehearsal for a possible, imagined future that just might (but more likely never will) occur in the individual's life in the real world. Movie-goers, no less than the readers of novels, actively engage with the symbols that film makers inscribe in the screen text. In so doing, they take a measure of control over elements of the fiction. Screened fiction has thus the potential to help the individual grow in self-awareness. Shifting its focus to the work of the film critic, the paper argues that, suitably adapted to the requirements of working with a pre-recorded film or tape, Jung's concept of the active imagination helps us to model, license, limit and endorse the subjective element in textual analysis. Because the method proposed makes it possible formally to recognize that the interpretation of fiction is inevitably integrated with the analyst's personality, interpretation is always a matter of a reader bringing a text into being rather than disinterring a pre-existing object.

Emotions↗
PubMed1993

Virological features of hepatitis C virus infection in hemodialysis patients.

The clinical and epidemiological relevance of circulating antibodies to hepatitis C virus (HCV) in hemodialysis patients is uncertain, since clinical signs of infection are often mild or absent, with alanine aminotransferase (ALT) values that are virtually always normal, and liver biopsies are only rarely performed. Determination of HCV RNA in serum is therefore critical for distinguishing chronic HCV infection from previous exposure to the virus. We studied HCV viremia by reverse transcription polymerase chain reaction (RT-PCR) in the 5'-noncoding region of the viral genome in 77 dialysis patients who were screened for anti-HCV by a second-generation enzyme-linked immunosorbent assay (the enzyme immunoassay II; Ortho HCV, 2nd generation, Ortho Diagnostic Systems Raritan, N.J.) and a second-generation recombinant immunoblot assay (Chiron Corporation and Ortho Diagnostic Systems) and prospectively evaluated for ALT elevations over a period of 5 years. Of 77 patients tested, 29 (38%) had active infection as shown by a positive PCR assay result, and of these, 26 were anti-HCV positive. Although a good correlation was found between circulating anti-HCV and HCV RNA in serum, 10 (28%) of 36 anti-HCV-positive patients were HCV RNA negative by PCR, suggesting either low levels of viremia or past exposure to HCV and subsequent recovery. On the other hand, 3 (7.3%) of 41 anti-HCV-negative patients had HCV RNA in their sera, indicating seronegative HCV infection. The ALT level had no predictive value for HCV infection, because it was repeatedly normal in 18 (62%) of 29 viremic patients. HCV genotyping was also performed and indicated that all four known genotypes of HCV were present in our group. In conclusion, serological assays are reliable for detecting exposure to HCV in hemodialysis patients; however, direct identification of the viral genome is required to document current infection.

Adolescent↗
PubMed1999

Virtual colonoscopy--technique and applications.

Virtual colonoscopy is a new method for evaluating the colon which uses thin section computed tomography of the clean air distended colon. The acquired computed tomography data is then subjected to computer manipulation to demonstrate the colonic mucosa. It is a safe, non-invasive, well-tolerated method that has potential as a method of colorectal cancer screening. This review will describe the technique, review preliminary results, and discuss the present and future applications of this technique.

Colon↗
PubMed2001

Phylogeography of the human mitochondrial haplogroup L3e: a snapshot of African prehistory and Atlantic slave trade.

The mtDNA haplogroup L3e, which is identified by the restriction site +2349 MboI within the Afro-Eurasian superhaplogroup L3 (-3592 HpaI), is omnipresent in Africa but virtually absent in Eurasia (except for neighbouring areas with limited genetic exchange). L3e was hitherto poorly characterised in terms of HVS-I motifs, as the ancestral HVS-I type of L3e cannot be distinguished from the putative HVS-I ancestor of the entire L3 (differing from the CRS by a transition at np 16223). An MboI screening at np 2349 of a large number of Brazilian and Caribbean mtDNAs (encompassing numerous mtDNAs of African ancestry), now reveals that L3e is subdivided into four principal clades, each characterised by a single mutation in HVS-I, with additional support coming from HVS-II and partial RFLP analysis. The apparently oldest of these clades (transition at np 16327) occurs mainly in central Africa and was probably carried to southern Africa with the Bantu expansion(s). The most frequent clade (transition at np 16320) testifies to a pronounced expansion event in the mid-Holocene and seems to be prominent in many Bantu groups from all of Africa. In contrast, one clade (transition at np 16264) is essentially restricted to Atlantic western Africa (including Cabo Verde). We propose a tentative L3e phylogeny that is based on 197 HVS-I sequences. We conclude that haplogroup L3e originated in central or eastern Africa about 46,000 (+/-14,000) years ago, and was a hitchhiker of much later dispersal and local expansion events, with the rise of food production and iron smelting. Enforced migration of African slaves to the Americas translocated L3e mitochondria, the descendants of which in Brazil and the Caribbean still reflect their different regional African ancestries.

Africa↗
PubMed2003

Knowledge and beliefs regarding type 2 diabetes mellitus in rural Mexico.

OBJECTIVE: To investigate adults with Type 2 diabetes mellitus (DM) in a rural area of Mexico in order to explore their knowledge and beliefs regarding diabetes. DESIGN: A pilot study was conducted in a rural town in Morelos, Mexico. Adults over the age of 40 were invited to participate in a screening program for DM, and those who had been previously diagnosed with Type 2 DM were invited for an interview to learn about their knowledge and beliefs regarding diabetes. RESULTS: The glucose screening project enrolled 521 participants, including 56 previously diagnosed with Type 2 DM. Interviews were conducted with 37 of those with previously diagnosed DM. Almost all individuals in the interview sample held causal explanations based on non-scientific beliefs. Home remedies were used by a majority, and most informants used one or more methods. Blood glucose monitoring was virtually non-existent. The most frequently reported source of social support was family members. Physicians appeared to be a less important source of support. CONCLUSION: Most respondents would like to improve management of their DM, and they try to do so with whatever resources they can afford; however, a lack of information and restricted economic resources appear to limit the availability of modern medical resources. Without the availability of glucose monitoring/screening programs and affordable medication, it appears unlikely that improved treatment of Type 2 DM will occur. Dietary changes and other management approaches may be best modified through family and community influence, instead of the individual lifestyle modification strategies described in the US Type 2 DM management model.

Adult↗
PubMed1997

A general method for identifying recessive diploid-specific mutations in Saccharomyces cerevisiae, its application to the isolation of mutants blocked at intermediate stages of meiotic prophase and characterization of a new gene SAE2.

We describe a general new approach for identifying recessive mutations that affect diploid strains of yeast Saccharomyces cerevisiae and the application of this method to the identification of mutations that confer an intermediate block in meiotic prophase chromosome metabolism. The method uses a temperature-sensitive conjugation mutation ste7-1 in combination with homothallism. The mutations of interest confer a defect in spore formation that is dependent upon a gene required for initiation of meiotic recombination and development of meiosis-specific chromosome structure (SPO11). Identified in this screen were null mutations of the DMC1 gene, nonnull mutations of RAD50 (rad50S), and mutations in three new genes designed SAE1, SAE2 and SAE3 (Sporulation in the Absence of Spo Eleven). Molecular characterization of the SAE2 gene and characterization of meiotic and mitotic phenotypes of sae2 mutants are also presented. The phenotypes conferred by a sae2 null mutation are virtually indistinguishable from those conferred by the previously identified nonnull mutations of RAD50 (rad50S). Most notably, both mutations confer only weak sensitivity to the radiomimetic agent methyl methane sulfonate (MMS) but completely block resection and turnover of meiosis-specific double-strand breaks. These observations provide further evidence that this constellation of phenotypes identifies a specific molecular function.

Amino Acid Sequence↗