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D Beach

Publications and source records attributed to D Beach.

At least 145 records · Page 8Linked to original sources
PubMed1987

Sucl+ encodes a predicted 13-kilodalton protein that is essential for cell viability and is directly involved in the division cycle of Schizosaccharomyces pombe.

Sucl+ was originally identified as a DNA sequence that, at high copy number, rescued Schizosaccharomyces pombe strains carrying certain temperature-sensitive alleles of the cdc2 cell cycle control gene. We determined the nucleotide sequence of a 1,083-base-pair Sucl+ DNA fragment and S1 mapped its 866-nucleotide RNA transcript. The protein-coding sequence of the gene is interrupted by two intervening sequences of 115 and 51 base pairs. The predicted translational product of the gene is a protein of 13 kilodaltons. A chromosomal gene disruption of Sucl+ was constructed in a diploid S. pombe strain. Germinating spores carrying a null allele of the gene were capable of very limited cell division, following which many cells became highly elongated. The Sucl+ gene was also strongly overexpressed under the control of a heterologous S. pombe promoter. Overexpression of Sucl+ is not lethal but causes a division delay such that cells are approximately twice the normal length at division. These data suggest that Sucl+ encodes a protein which plays a direct role in the cell division cycle of S. pombe.

Alleles↗
PubMed1986

Homology between the ran1+ gene of fission yeast and protein kinases.

The ran1+ gene of the fission yeast Schizosaccharomyces pombe is a negative regulator of both sexual conjugation and meiosis. The nucleotide sequence of the gene has been determined and contains a region of open reading frame (ORF) capable of encoding a protein of 52,000 daltons. S1 nuclease analysis of ran1+-encoded RNA showed that the ORF was spanned by an uninterrupted transcript. A fragment of DNA containing the entire ran1+ gene was expressed in a bacterial expression vector and found to encode the expected product of 52,000 daltons. The putative ran1+ gene product shares significant sequence homology with known protein kinases. The level of the ran1+ transcript was similar in vegetative and meiotic cells suggesting that the ran1+ protein product rather than its transcript is regulated during sexual differentiation.

Amino Acid Sequence↗
PubMed1986

Involvement of ras in sexual differentiation but not in growth control in fission yeast.

The function of the ras gene of Schizosaccharomyces pombe has been studied by constructing null and activated alleles of this gene. An activated allele (Val (12)) inhibits conjugation but has no effect on cell growth, entry into stationary phase or sporulation. The phenotype of Val (12) is distinct from that caused by elevating the intracellular level of cAMP. This supports the hypothesis that ras of fission yeast does not modulate adenylate cyclase in a manner analogous to S. cerevisiae RAS. Introduction of a human ras sequence into fission yeast cells containing a non-functional null allele of ras restored the sexual differentiation process thus indicating that the human sequence can complement S. pombe ras. Our data suggest that although ras genes are highly conserved across a considerable evolutionary divide, the cellular function of the ras gene product varies in different organisms.

Journal Article↗
PubMed1986

The fission yeast cell cycle control gene cdc2: isolation of a sequence suc1 that suppresses cdc2 mutant function.

A DNA fragment called suc1 has been found to rescue cells mutated in the cell cycle control gene cdc2 of the fission yeast Schizosaccharomyces pombe. The suppressing activity of suc1 is observed when it is present on a multicopy number plasmid. The gene does not hybridize to cdc2 and maps elsewhere in the genome. Its effect is cdc2 allele specific suggesting that it interacts directly with the cdc2 gene function.

Base Sequence↗
PubMed1986

Vectors for the construction of gene banks and the integration of cloned genes in Schizosaccharomyces pombe and Saccharomyces cerevisiae.

We have constructed a variety of vectors for use in both budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe). Four of these, pDB262, pWH4, pWH5, and pMAK262, have positive selection for the insertion of cloned DNA, making them convenient for the construction of gene banks. pDB262, pWH4 and pWH5 contain the 2 mu ARS and the LEU2 gene from S. cerevisiae and can be used for gene isolation. They can also be converted into integration vectors for use in the genetic mapping of cloned sequences. pMAK262 contains only the LEU2 gene from budding yeast and can be used to screen for ARS elements or for gene integration. We also describe two other integration vectors, pDAM3 and pDAM6, which have a variety of restriction sites suitable for subcloning.

Chromosome Mapping↗
PubMed1986

Site-specific mutagenesis of cdc2+, a cell cycle control gene of the fission yeast Schizosaccharomyces pombe.

The cdc2+ gene of Schizosaccharomyces pombe is homologous to the CDC28 gene of Saccharomyces cerevisiae. Both genes share limited homology with vertebrate protein kinases and have protein kinase activity. cdc2+ has been subjected to mutagenesis in vitro. A null allele of the gene, constructed by insertion of the S. cerevisiae LEU2 gene into a site within the gene, has a phenotype similar to that of many temperature-sensitive alleles of cdc2. Mutations within the predicted ATP-binding site and in a region which may be a site of phosphorylation result in loss of cdc2+ activity. A single substitution of Gly-146 to Asp-146 has been identified in cdc2-1w, a dominant activated allele of the gene. The four introns within the cdc2+ gene have been deleted. The resulting gene not only functions in fission yeast but also rescues cdc28(Ts) strains of S. cerevisiae, a property which is not shared by the genomic cdc2+ gene.

Alleles↗
PubMed1985

ran1+ controls the transition from mitotic division to meiosis in fission yeast.

We have investigated the genetic and physiological control of meiosis in fission yeast. Nutritionally depleted h+/h- diploid cells become irreversibly commited to meiosis immediately prior to the initiation of premeiotic S phase. Premeiotic DNA synthesis requires matP+, matM+, mei2+ and mei3+ but not the mitotic cell cycle control gene, cdc2+. ran1+ is an essential gene, loss of which provokes sexual conjugation, premeiotic DNA synthesis, pseudo-meiosis and the sporulation of haploid cells. Our experiments suggest that sexual differentiation is achieved physiologically by the inhibition of ran1+ activity in a two-step process. In the first step, partial inhibition of ran1+ in starved haploid cells, leads to cell cycle arrest in G1 followed by sexual conjugation. In the second step, a pathway requiring the matP+, matM+ and mei3+ genes of the newly-formed zygote, further inhibits ran1+ and thereby commits the cell to meiosis. mei2+ is required for meiotic commitment after full inhibition of ran1+. ran1+ is normally essential for vegetative cell reproduction but is inessential in cells which have abnormally high levels of cAMP-dependent protein kinase. We propose that the ran1+ gene encodes a highly controlled protein kinase which shares key substrates with cAMP-dependent protein kinase.

Alleles↗
PubMed1984

Ectopic pregnancy effects on the ipsilateral fallopian tube epithelium--an ultrastructural study.

Ectopic pregnancy specimens of 6 human Fallopian tube fimbrial epithelia were studied utilizing ultrastructural, cytochemical and morphometric methods. The observations were compared with those made on 12 intrauterine pregnancy specimens. The morphometric measurements indicate earlier onset of atrophic changes in ectopic pregnancy. Deciliation in Ectopic pregnancy preceded that observed in intrauterine pregnancy. Cell height also decreased earlier in ectopic pregnancy than in intrauterine pregnancy. In addition, during the 1st trimester, ultrastructural localization of calcium revealed that, in ectopic pregnancy, the mitochondrial calcium, which was observed in intrauterine specimens, was shifted into the cytoplasmic compartment of the ciliary cell. Consequently, cytoplasmic calcium was found in the ectopic specimens and was less evident in the intrauterine specimens. Thus, a local atrophic effect is evident in ectopic pregnancy, which appears earlier than the atrophic process found in intrauterine pregnancy.

Acid Phosphatase↗
PubMed1983

Menstrual-cycle-dependent and -independent features of the human Fallopian tube fimbrial epithelium: an ultrastructural and cytochemical study.

Ultrastructural and cytochemical features of 100 specimens of human Fallopian tube fimbrial epithelium were studied to determine whether they were dependent on or independent of the ovarian hormones. Characteristics which were independent of hormonal control included the presence of alkaline phosphatase reaction product along the apical cell membrane of the secretory cell and its absence in the ciliary cell. Acid phosphatase reaction product was found in ciliary and secretory cell lysosomes in similar numbers and calcium deposits were observed in ciliary and secretory cell nuclei, nucleoli and cell membranes. On the other hand, characteristics dependent on stages of the cycle included the presence of mitochondrial-bound calcium during the preovulatory phase and its depletion during the periovulatory phase. The same sequence was noticed in the content of the large ciliary cell perinuclear globules, which displayed accumulations of glycogen and lipid in preovulatory phase and their depletion during the periovulatory phase. It seems that during the periovulatory phase the increased metabolic activity of the cells is accompanied by utilization of some of the material stored within the cells.

Alkaline Phosphatase↗
PubMed1982

Functionally homologous cell cycle control genes in budding and fission yeast.

The cdc 2 (previously called wee 2) cell cycle start gene of Schizosaccharomyces pombe, which is required for start and the control of mitosis, has been isolated from an S. pombe gene bank by complementation of a cdc 2 mutation. A functionally homologous sequence which complements the cdc 2 mutation has also been isolated from a Saccharomyces cerevisiae gene bank and this sequence has been shown to contain the cdc 28 cell cycle start gene of S. cerevisiae. It is concluded that the cdc 2 and cdc 28 genes perform homologous cell cycle control functions in the two organisms.

Ascomycota↗
PubMed1982

Ultrastructural localization of alkaline and acid phosphatases in the human fallopian tube epithelium during the menstrual cycle.

Ultrastructural and cytochemical methods were utilized to study the human Fallopian tube fimbrial epithelium during the different stages of the menstrual cycle. Alkaline phosphatase reaction product was located along the apical and lateral plasma membranes of the secretory cells only, regardless of the stage of the cycle. The ciliated cells were almost devoid of any reaction product at all stages of the cycle. Acid phosphatase reaction product depicted the lysosomes. These appeared as electron-dense bodies, of almost equal numbers in the ciliated and the secretory cells at all stages of the cycle. Thus the number of lysosomes did not vary appreciable during the different stages of the menstrual cycle. Many lipid droplets were found in both cells; these were rimmed by acid phosphatase reaction product, and some were partially enveloped by electron-dense bodies containing acid phosphatase deposits. Acid phosphatase deposits were also found on the inner face of Golgi vesicles.

Acid Phosphatase↗
PubMed1982

Construction of a Schizosaccharomyces pombe gene bank in a yeast bacterial shuttle vector and its use to isolate genes by complementation.

A gene bank of partial Sau3A restriction fragments of S. pombe DNA has been constructed in the plasmid vector, pDB248', which is capable of high frequency transformation of S. pombe. Procedures are described which enable plasmids to be recovered from S. pombe by their reintroduction into E. coli. These methods have been used to detect the S. pombe genes lys 1+, ade 6+ and his 2+ in the gene bank by complementation of mutant gene functions, and to physically isolate the lys 1+ gene.

Ascomycota↗
PubMed1982

Juxtanuclear globule of the human fimbrial epithelium ciliary cell: a histo- and cytochemical study.

Microbiopsies of human Fallopian tube fimbrial epithelium were obtained during routine gynecological operations, and during pregnancy while undergoing hysterectomy in the first trimester or cesarean section in the third trimester. Specimens were studied under light and electron microscopes utilizing histo- and cytochemical techniques. Large juxtanuclear globules were demonstrated in the ciliary cell at all stages of the cycle. During the proliferative phase, these globules contained large lipid droplets and glycogen rosettes. The content of the globules in the early luteal phase was mostly amorphous electron-lucid material which failed to stain with PAS, alcian blue and the Millon reaction. However, reaction products of acid phosphatase as well as calcium precipitate were scattered in them as discrete granules. The same type of globule was found in early pregnancy. During late luteal phase and late pregnancy, the content of the globule was once again composed of lipids and glycogen. It seems that lipid and glycogen accumulate during the preovulatory phase, while depletion and dispersion of these substances occur in the periovulatory phase, probably due to increased energy utilization. Late luteal phase revealed subsequent replenishment of these reserves, as was also revealed in late pregnancy.

Acid Phosphatase↗
PubMed1982

Ultrastructural localization of calcium in human uterine tube epithelial cells.

Microbiopsies of 38 specimens of human Fallopian tube fimbrial epithelium obtained during hysterosalpingectomy operations were processed for electron microscopic observation. Calcium localization was demonstrated utilizing the pyroantimonate-osminium-tetroxide technique. Calcium deposits were consistently observed as scattered granules in the nuclei, nucleoli, and cell membranes of secretory and ciliary cells regardless of the stage of the menstrual cycle. On the other hand, mitochondrial-bound calcium was observed in the ciliary cells during the preovulatory phase, coinciding with relatively high estrogen levels, and was not found during the peri- and postovulatory phases of the menstrual cycle. It appears that there is cellular calcium which is relatively stable and is probably part of the structural components of the cells. The ciliary cell mitochondrial calcium appears to be more labile and is therefore available for mobilization and utilization in the metabolic processes associated with the periovulatory phase.

Adult↗
PubMed1981

Human fallopian tube epithelium cytochemistry in the first and third trimesters of pregnancy.

The human Fallopian tube fimbrial epithelium was histo- and cytochemically studied in the first and third trimesters of pregnancy. In the first trimester morphometric measurements confirmed a decrease in cell size and a reduction in ciliary cell count. The ciliary cell population was surprisingly glycogen-poor, and some of the cell contained, among normal organelles, lipid accumulation, lamellated bodies and nuclei with slightly condensed chromatin. Some had defective cilia and basal bodies. Large globules, containing few lipid droplets and glycogen rosettes were demonstrated. The bulk of the globules, however, contained an unidentified electron-lucid substance, negative to PAS, Alcian blue, OsO4 and the Millon reactions, but positive to acid phosphatase reaction, the products of which appeared dispersed. The nonciliary cell population was heterogeneous; some appeared almost devoid of microvilli and had dilated RER and SER cisternae, lamellated bodies and condensed nuclear chromatin. In some cells a single centrally located cilium was noticed. Other nonciliary cells had extensive microvilli and appeared less atrophied. In the third trimester morphometric, as well as cytochemical methods indicated that the regressive process was beginning to reverse itself. Alkaline-phosphatase reaction products appeared along the apical and lateral membranes of the nonciliary cell. Acid-phosphatase reaction products depicted the lysosomes, present in both types of cells.

Acid Phosphatase↗
PubMed1980

Isolation of chromosomal origins of replication in yeast.

Origins of replication have been identified in the DNA of viruses, mitochondria, bacterial plasmids and the bacterial chromosome. However, origins of replication of eukaryote chromosomes have remained elusive because of the large size and sequence complexity of chromosomes and in particular for want of a suitable assay for their detection. Recent development of techniques for genetic transformation of yeast by autonomously replicating cytoplasmic plasmids now makes it possible to search for eukaryote origins in a manner analogous to that used for bacteria. Here we describe the construction and properties of a plasmid which contains no effective eukaryote replication origin and whose efficiency of replication in yeast is greatly enhanced by insertion of certain fragments of yeast chromosomal DNA. We believe these to contain replication origins, since yeast transformants are shown to contain copies of the transforming plasmids.

Base Sequence↗