Dramatically diverse S. pombe wtf meiotic drivers all display high gamete-killing efficiency

AbstractMeiotic drivers are selfish genetic loci that force their transmission into more than 50% of the viable gametes made by heterozygotes. Meiotic drivers are known to cause infertility in a diverse range of eukaryotes and are predicted to affect the evolution of genome structure and meiosis. The wtf gene family of Schizosaccharomyces pombe includes both meiotic drivers and drive suppressors and thus offers a tractable model organism to study drive systems. Currently, only a handful of wtf genes have been functionally characterized and those genes only partially reflect the diversity of the wtf gene family. In this work, we functionally test 22 additional wtf genes. We identify eight new drivers that share between 30-90% amino acid identity with previously characterized drivers. Despite the vast divergence between these genes, they generally drive into >85% gametes when heterozygous. We also find three new wtf genes that suppress drive, including two that also act as autonomous drivers. Additionally, we find that wtf genes do not underlie a weak (64%) transmission bias caused by a locus or loci on chromosome 1. Finally, we find that some Wtf proteins have expression or localization patterns that are distinct from the poison and antidote proteins encoded by drivers and suppressors, suggesting some wtf genes may have non-meiotic drive functions. Overall, this work expands our understanding of the wtf gene family and the burden selfish driver genes impose on S. pombe.Article SummaryDuring gametogenesis, the two gene copies at a given locus, known as alleles, are each transmitted to 50% of the gametes (e.g. sperm). However, some alleles cheat so that they are found in more than the expected 50% of gametes, often at the expense of fertility. This selfish behavior is known as meiotic drive. Some members of the wtf gene family in the fission yeast, Schizosaccharomyces pombe, kill the gametes (spores) that do not inherit them, resulting in meiotic drive favoring the wtf allele. Other wtf genes act as suppressors of drive. However, the wtf gene family is diverse and only a small subset of the genes has been characterized. Here we analyze the functions of other members of this gene family and found eight new drivers as well as three new suppressors of drive. Surprisingly, we find that drive is relatively insensitive to changes in wtf gene sequence as highly diverged wtf genes execute gamete killing with similar efficiency. Finally, we also find that the expression and localization of some Wtf proteins are distinct from those of known drivers and suppressors, suggesting that these proteins may have non-meiotic drive functions.

Download Full-text

Isolation and Characterization Of Rice R Genes: Evidence for Distinct Evolutionary Paths in Rice and Maize

Genetics ◽

10.1093/genetics/142.3.1021 ◽

1996 ◽

Vol 142 (3) ◽

pp. 1021-1031 ◽

Cited By ~ 3

Author(s):

Jianping Hu ◽

Beth Anderson ◽

Susan R Wessler

Keyword(s):

Gene Family ◽

Gene Families ◽

Chromosome 1 ◽

R Gene ◽

R Genes ◽

Helix Loop Helix ◽

Isolation And Characterization ◽

Undetermined Function ◽

Evolutionary Paths

Abstract R and B genes and their homologues encode basic helix-loop-helix (bHLH) transcriptional activators that regulate the anthocyanin biosynthetic pathway in flowering plants. In maize, R/B genes comprise a very small gene family whose organization reflects the unique evolutionary history and genome architecture of maize. To know whether the organization of the R gene family could provide information about the origins of the distantly related grass rice, we characterized members of the R gene family from rice Oryza sativa. Despite being a true diploid, O. sativa has at least two R genes. An active homologue (Ra) with extensive homology with other R genes is located at a position on chromosome 4 previously shown to be in synteny with regions of maize chromosomes 2 and 10 that contain the B and R loci, respectively. A second rice R gene (Rb) of undetermined function was identified on chromosome 1 and found to be present only in rice species with AA genomes. All non-AA species have but one R gene that is Ra-like. These data suggest that the common ancestor shared by maize and rice had a single R gene and that the small R gene families of grasses have arisen recently and independently.

Download Full-text

Isolation and Characterization of Nrf1p, a Novel Negative Regulator of the Cdc42p GTPase in Schizosaccharomyces pombe

Genetics ◽

10.1093/genetics/154.1.155 ◽

2000 ◽

Vol 154 (1) ◽

pp. 155-165 ◽

Cited By ~ 1

Author(s):

Janet M Murray ◽

Douglas I Johnson

Keyword(s):

Schizosaccharomyces Pombe ◽

Fluorescent Protein ◽

Amino Acid Identity ◽

Negative Regulator ◽

Nucleotide Exchange ◽

Cortical Actin ◽

Isolation And Characterization ◽

Nucleotide Exchange Factor ◽

Green Fluorescent ◽

Vacuolar Membranes

Abstract The Cdc42p GTPase and its regulators, such as the Saccharomyces cerevisiae Cdc24p guanine-nucleotide exchange factor, control signal-transduction pathways in eukaryotic cells leading to actin rearrangements. A cross-species genetic screen was initiated based on the ability of negative regulators of Cdc42p to reverse the Schizosaccharomyces pombe Cdc42p suppression of a S. cerevisiae cdc24ts mutant. A total of 32 S. pombe nrf (negative regulator of Cdc forty two) cDNAs were isolated that reversed the suppression. One cDNA, nrf1+, encoded an ~15 kD protein with three potential transmembrane domains and 78% amino-acid identity to a S. cerevisiae gene, designated NRF1. A S. pombe Δnrf1 mutant was viable but overexpression of nrf1+ in S. pombe resulted in dose-dependent lethality, with cells exhibiting an ellipsoidal morphology indicative of loss of polarized cell growth along with partially delocalized cortical actin and large vacuoles. nrf1+ also displayed synthetic overdose phenotypes with cdc42 and pak1 alleles. Green fluorescent protein (GFP)-Cdc42p and GFP-Nrf1p colocalized to intracellular membranes, including vacuolar membranes, and to sites of septum formation during cytokinesis. GFP-Nrf1p vacuolar localization depended on the S. pombe Cdc24p homolog Scd1p. Taken together, these data are consistent with Nrf1p functioning as a negative regulator of Cdc42p within the cell polarity pathway.

Download Full-text

The YPT Gene Family of Schizosaccharomyces Pombe

The Superfamily of ras-Related Genes ◽

10.1007/978-1-4684-6018-6_3 ◽

1991 ◽

pp. 23-29

Author(s):

John Armstrong ◽

Erica Fawell ◽

Sally Hook ◽

Alison Pidoux ◽

Mark Craighead

Keyword(s):

Gene Family ◽

Schizosaccharomyces Pombe

Download Full-text

Schizosaccharomyces pombe map3+ encodes the putative M-factor receptor.

Molecular and Cellular Biology ◽

10.1128/mcb.13.1.80 ◽

1993 ◽

Vol 13 (1) ◽

pp. 80-88 ◽

Cited By ~ 75

Author(s):

K Tanaka ◽

J Davey ◽

Y Imai ◽

M Yamamoto

Keyword(s):

Schizosaccharomyces Pombe ◽

Nitrogen Starvation ◽

Transmembrane Protein ◽

Strong Support ◽

Amino Acid Identity ◽

Nucleotide Sequence Analysis ◽

Mating Pheromone ◽

Pheromone Signaling ◽

P Factor ◽

Coding Capacity

A defect in the map3 gene of the fission yeast Schizosaccharomyces pombe causes h+ mating-type-specific sterility. This gene was cloned by complementation. Nucleotide sequence analysis showed that it has a coding capacity of 365 amino acids. The deduced map3 gene product is a putative seven-transmembrane protein and has 20.0% amino acid identity with the a-factor receptor of Saccharomyces cerevisiae, encoded by STE3. It is also homologous with the Ustilago maydis mating pheromone receptors. The map3 gene is expressed in h+ cells but not in h- cells, and the transcripts are induced in response to nitrogen starvation. h+ cells defective in map3 do not respond to purified M-factor. When map3 is expressed ectopically in h- cells, they apparently acquire the ability to respond to the M-factor produced by themselves. The gpa1 gene, which encodes the alpha-subunit of a G-protein presumed to couple with the mating pheromone receptors, is essential for this function of map3. These observations strongly suggest that map3 encodes the M-factor receptor. Furthermore, this study provides strong support for the notion that pheromone signaling is essential for initiation of meiosis in S. pombe and that either M-factor signaling or P-factor signaling alone is sufficient.

Download Full-text

Ectopic Expression of Virus Innexins in Heliothis virescens Disrupts Hemocyte-Mediated Encapsulation and Host Viability

10.1101/788661 ◽

2019 ◽

Author(s):

Peng Zhang ◽

Matthew W Turnbull

Keyword(s):

Gene Family ◽

Gap Junction ◽

Host Range ◽

Heliothis Virescens ◽

Genome Structure ◽

Ectopic Expression ◽

Recombinant Baculovirus ◽

Gene Families ◽

Recombinant Baculoviruses ◽

Susceptible Host

1.AbstractPolydnaviruses are dsDNA viruses associated with endoparasitoid wasps. Delivery of the virus during parasitization of a caterpillar and subsequent virus gene expression is required for production of an amenable environment for parasitoid offspring development. Consequently, understanding of Polydnavirus gene function provides insight into mechanisms of host susceptibility and parasitoid wasp host range. Polydnavirus genes predominantly are arranged in multimember gene families, one of which is the vinnexins, which are virus homologues of insect gap junction genes, the innexins. Previous studies of Campoletis sonorensis Ichnovirus Vinnexins using various heterologous systems have suggested the four encoded members may provide different functionality in the infected caterpillar host. Here, we expressed two of the members, vnxG and vnxQ2, using recombinant baculoviruses in susceptible host, the caterpillar Heliothis virescens. Following intrahemocoelic injections, we observed >90% of hemocytes (blood cells) were infected, producing recombinant protein. Larvae infected with a vinnexin-recombinant baculovirus exhibited significantly reduced molting rates relative to larvae infected with a control recombinant baculovirus and mock infected larvae. Similarly, larvae infected with vinnexin-recombinant baculoviruses were less likely to molt relative to controls, and showed reduced ability to encapsulate chromatography beads in an immune assay. In most assays, the VnxG protein was associated with more severe pathology than VnxQ2. These results, in light of previous findings, support that Polydnavirus Vinnexin gene family members may provide complementary, rather than redundant, effects. This in turn indicates a need to test gene family member functionality across infected hosts for effects to determine member contribution to host range.2.ImportancePolydnaviruses are obligate mutualistic associates of highly speciose wasp taxa that parasitize caterpillars. Expression of Polydnavirus-encoded genes in hosts parasitized by wasps is necessary for successful parasitization, and an unusual genome structure including multiple-membered gene families is hypothesized to contribute to host manipulation. We have tested this hypothesis by in vivo expression of two members of a family of Polydnavirus homologues of Innexins, or insect gap junction proteins. Previous findings demonstrated that the two Vinnexins induce different physiological alterations in heterologous systems. Here, in host caterpillars, we observed differential alteration by the two proteins of host immune cell (hemocyte) bioelectrical physiology and the immune response of encapsulation. Not only do our data suggest a linkage between cellular bioelectricity and immunity in insects, but they support that gene family expansion has functional consequences to both Polydnavirus and host wasp success.

Download Full-text

A toolbox of Stable Integration Vectors (SIV) in the fission yeast Schizosaccharomyces pombe

10.1101/808329 ◽

2019 ◽

Author(s):

Aleksandar Vještica ◽

Magdalena Marek ◽

Pedro N’kosi ◽

Laura Merlini ◽

Gaowen Liu ◽

...

Keyword(s):

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Model Organism ◽

Experimental System ◽

Single Copy ◽

Cell Physiology ◽

Large Set ◽

Stable Integration ◽

Wide Range ◽

Fluorescent Tags

AbstractSchizosaccharomyces pombe is a widely used model organism that resembles higher eukaryotes in many aspects of cell physiology. Its popularity as an experimental system partially stems from the ease of genetic manipulations, where the innate homology-targeted repair is exploited to precisely edit the genome. While vectors to incorporate exogenous sequences into the chromosomes are available, most are poorly characterized. Here we show that commonly used fission yeast vectors, which upon integration produce repetitive genomic regions, yield unstable genomic loci. We overcome this problem by designing a new series of Stable Integration Vectors (SIV) that target four different prototrophy genes. SIV produce non-repetitive, stable genomic loci and integrate predominantly as single copy. Additionally, we develop a set of complementary auxotrophic alleles that preclude false-positive integration events. We expand the vector series to include antibiotic resistance markers, promoters, fluorescent tags and terminators, and build a highly modular toolbox to introduce heterologous sequences. Finally, as proof of concept, we generate a large set of ready-to-use, fluorescent probes to mark organelles and cellular processes with a wide range of applications in fission yeast research.

Download Full-text

PATH-50. ROUTINE MOLECULAR DIAGNOSIS OF GLIOMA PATIENTS USING A GLIOMA-SPECIFIC NGS PANEL

Neuro-Oncology ◽

10.1093/neuonc/noz175.646 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi154-vi155

Author(s):

Koji Yoshimoto ◽

Nayuta Higa ◽

Hajime Yonezawa ◽

Hiroyuki Uchida ◽

Toshiaki Akahane ◽

...

Keyword(s):

Molecular Diagnosis ◽

Gene Mutations ◽

Chromosome 1 ◽

Clinical Samples ◽

Driver Gene ◽

Driver Genes ◽

Chromosome 1P ◽

Ffpe Tumor ◽

Grade Ii ◽

Key Driver

Abstract AIM The 2016 WHO classification requires molecular diagnosis in routine glioma diagnostics. However, analysis of key driver gene mutations and chromosome 1p/19q co-deletions cannot be performed in a single platform. In this study, we evaluated the feasibility of a glioma-specific NGS panel for molecular diagnosis of glioma patients. MATERIALS AND METHODS We developed a glioma-specific NGS panel consisting of 48 genes, including glioma-relevant key driver genes and 21 genes mapped to chromosome 1 and 19. DNA was extracted from formaldehyde fixed-paraffin embedded (FFPE) tumor tissues histologically identified by a pathologist, and from patient-derived blood as a control. In this system, we implemented a molecular barcodes method to enhance confidence in clinical samples and analyzed 80 glioma patients (Grade II: 17 cases, Grade III: 16 cases, Grade IV: 47 cases). RESULTS From these 80 cases, IDH1 and H3F3A mutations were detected in 23 cases (29%) and 2 cases (5%), respectively. The 1p/19q co-deletion was detected in 15 cases (19%), with all cases also containing IDH1 mutations. In Grade IV cases, EGFR, PDGFR, and FGFR mutations were detected in 6% (amp 19%), 9%, and 4% (amp 17%) of cases, respectively. PTEN, TP53, NF1, RB1, and CDKN2A mutations were detected in 37% (del 72%), 45% (del 13%), 21% (del 23%), 15% (del 60%), and 2% (del 53%) of cases, respectively. CONCLUSION Diagnosis of glioma patients with this glioma-specific NGS panel is feasible.

Download Full-text

Genomic Cloning, Physical Mapping, and Expression of Human Type 2 Cystatin Genes

Critical Reviews in Oral Biology & Medicine ◽

10.1177/10454411930040034401 ◽

1993 ◽

Vol 4 (3) ◽

pp. 573-580 ◽

Cited By ~ 11

Author(s):

D.P. Dickinson ◽

M. Thiesse ◽

L.D. Dempsey ◽

S.J. Millar

Keyword(s):

Gene Family ◽

Cystatin C ◽

Small Subset ◽

Gene Encoding ◽

Tandem Gene Duplication ◽

Rnase Protection ◽

Tissue Specific ◽

Genes Encoding ◽

Cystatin Gene

Humans carry one gene encoding cystatin C and six to eight genes with homology to an S-like cystatin hybridization probe. However, the precise composition and organization of the cystatin gene family remains to be established. Further, the pattern of tissue-specific expression has not been fully defined. We have previously shown that the type 2 cystatin genes are clustered together in a ca. 270 kb region (the CST locus). To determine the structure of this region, we have sought to clone the entire CST locus. Our approach has been to isolate cosmid and lambda genomic clones carrying cystatin genes and then to use "walk" probes derived from the end regions of these clones to identify other clones, which extend them. To date, we have obtained over 320 kb of distinct sequences. Based on restriction maps, sequencing, and hybridization analyses, we have identified eight apparently nonallelic copies of cystatin genes. These include one gene for cystatin C, four closely related genes encoding S-like cystatins, and three genes encoding relatively divergent sequences. Complete assembly of these clones into an unambiguous contiguous sequence is hampered by the presence of flanking locus-specific repetitive-like sequences. RNase protection assays used to characterize the tissue-specific patterns of expression showed that cystatin C is expressed at modest, comparable levels in all tissues examined, whereas expression of the CST 1 gene, encoding cystatin SA-I, was found to be restricted to a small subset of tissues, with the highest level in the submandibular gland. The cystatin gene family, therefore, appears to have evolved by tandem gene duplication, followed by the acquisition of control elements influencing the location and level of expression. The cystatin gene family is, thus, a potentially powerful system for the future study of mechanisms of gene regulation in human salivary glands.

Download Full-text