Biomedical subjects

C Ginther

Publications and source records attributed to C Ginther.

10 recordsLinked to original sources

PubMed1998

A homologue of Drosophila aurora kinase is oncogenic and amplified in human colorectal cancers.

Genetic and biochemical studies in lower eukaryotes have identified several proteins that ensure accurate segregation of chromosomes. These include the Drosophila aurora and yeast Ipl1 kinases that are required for centrosome maturation and chromosome segregation. We have identified two human homologues of these genes, termed aurora1 and aurora2, that encode cell-cycle-regulated serine/threonine kinases. Here we demonstrate that the aurora2 gene maps to chromosome 20q13, a region amplified in a variety of human cancers, including a significant number of colorectal malignancies. We propose that aurora2 may be a target of this amplicon since its DNA is amplified and its RNA overexpressed, in more than 50% of primary colorectal cancers. Furthermore, overexpression of aurora2 transforms rodent fibroblasts. These observations implicate aurora2 as a potential oncogene in many colon, breast and other solid tumors, and identify centrosome-associated proteins as novel targets for cancer therapy.

3T3 Cells↗

PubMed1997

Extent of heterogeneity in mitochondrial DNA of sub-Saharan African populations.

Variation in the mitochondrial DNA (mtDNA) control region as detected by sequence-specific oligonucleotide (SSO) probes is described for 381 individuals from nine sub-Saharan African populations. Population diversity estimates for SSO types ranged from 0.23 to 0.97, while 102 SSO types were detected, none of these types was shared by more than four populations. Eighteen types occurred in > or = 10% of individuals in some populations; of these, 11 were population-specific. One type occurred in 15% of the total sample, but was shared among only three populations. African SSO types were characterized by high frequencies of blank variants, indicating that there was additional variation present at the nucleotide sequence level in regions where SSO probes hybridize. Analyses of molecular variance (AMOVA) incorporating genetic distances between SSO types showed that 30% of the total variation was due to differences among populations, indicating that there is statistically significant heterogeneity (p < 0.001). An AMOVA on mtDNA control region nucleotide sequence data from 12 populations showed that including all additional variation present at the sequence level increased the variance due to population subdivision to 34% (p < 0.001). Overall, when considering both the low diversity within some populations and high heterogeneity among populations, SSO typing of mtDNA may not be a desirable forensic DNA typing method for continental African populations. Further mtDNA sampling of African-derived populations of North America should be carried out to determine how much of the continental African mtDNA variation is of forensic significance. However, the existence of extensive mtDNA control region nucleotide sequence variation in African populations means that control region sequencing is still appropriate in forensic cases requiring mtDNA analysis.

Africa, Central↗

PubMed1996

Mitochondrial D-loop "signatures" produced by low-stringency single specific primer PCR constitute a simple comparative human identity test.

We have developed a technique called "LSSP-PCR" (low-stringency single specific primer PCR) that detects single or multiple mutations in DNA. A purified DNA fragment is submitted to PCR by using a single primer specific for one of the extremities of the fragment, under conditions of very low stringency. The primer hybridizes specifically to its complementary extremity and nonspecifically to multiple sites within the fragment, in a sequence-dependent manner. A complex set of reaction products is thus created that, when separated by electrophoresis, constitutes a unique "gene signature." We here report the application of LSSP-PCR to the detection of sequence variation in the control (D-loop) region of human mtDNA, which is known to differ significantly between unrelated individuals. We prepared human DNA samples from blood and amplified a 1024-bp portion of the mtDNA control region, using primers L15996 and H408. The amplified mtDNA fragments were then reamplified under LSSP-PCR conditions by using L15996 or H408 as drivers to produce complex signatures that always differed between unrelated individuals and yet were highly reproducible. In contrast, all mother-child pairs tested were identical, as expected from the matrilineal inheritance of mtDNA. Thus, the use of LSSP-PCR to produce D-loop signatures constitutes a powerful new technique for mtDNA-based comparative identity testing.

Base Sequence↗

PubMed1993

Genetic variation among the Mapuche Indians from the Patagonian region of Argentina: mitochondrial DNA sequence variation and allele frequencies of several nuclear genes.

DNA samples from 60 Mapuche Indians, representing 39 maternal lineages, were genetically characterized for (1) nucleotide sequences of the mtDNA control region; (2) presence or absence of a nine base duplication in mtDNA region V; (3) HLA loci DRB1 and DQA1; (4) variation at three nuclear genes with short tandem repeats; and (5) variation at the polymorphic marker D2S44. The genetic profile of the Mapuche population was compared to other Amerinds and to worldwide populations. Two highly polymorphic portions of the mtDNA control region, comprising 650 nucleotides, were amplified by the polymerase chain reaction (PCR) and directly sequenced. The 39 maternal lineages were defined by two or three generation families identified by the Mapuches. These 39 lineages included 19 different mtDNA sequences that could be grouped into four classes. The same classes of sequences appear in other Amerinds from North, Central, and South American populations separated by thousands of miles, suggesting that the origin of the mtDNA patterns predates the migration to the Americas. The mtDNA sequence similarity between Amerind populations suggests that the migration throughout the Americas occurred rapidly relative to the mtDNA mutation rate. HLA DRB1 alleles 1602 and 1402 were frequent among the Mapuches. These alleles also occur at high frequency among other Amerinds in North and South America, but not among Spanish, Chinese or African-American populations. The high frequency of these alleles throughout the Americas, and their specificity to the Americas, supports the hypothesis that Mapuches and other Amerind groups are closely related.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗

PubMed1992

Identifying individuals by sequencing mitochondrial DNA from teeth.

Mitochondrial DNA (mtDNA) was extracted from teeth stored from 3 months to 20 years, including teeth from the semi-skeletonized remains of a murder victim which had been buried for 10 months. Tooth donors and/or their maternal relatives provided blood or buccal cells, from which mtDNA was also extracted. Enzymatic amplification and direct sequencing of roughly 650 nucleotides from two highly polymorphic regions of mtDNA yielded identical sequences for each comparison of tooth and fresh DNA. Our results suggest that teeth provide an excellent source for high molecular weight mtDNA that can be valuable for extending the time in which decomposed human remains can be genetically identified.

Base Sequence↗

PubMed1992

Roles of rpoD, spoIIF, spoIIJ, spoIIN, and sin in regulation of Bacillus subtilis stage II sporulation-specific transcription.

Bacillus subtilis strains containing defects in the sporulation gene spoIIF (kinA), spoIIJ (kinA), or spoIIN (ftsA) cannot transcribe the sigma E-dependent gene spoIID. Results presented here and by other workers demonstrate that the spoIIF, spoIIJ, and spoIIN gene products control spoIID transcription indirectly by coordinating the induction of the spoIIGAB, spoIIE, and spoIIAC operons, which are required for sigma E synthesis and processing. Sporulation competence and spoIIGAB, spoIIE, and spoIIAC transcription were restored in spoIIF, spoIIJ, and spoIIN mutants by introduction of crsA47, a mutation in the major vegetative sigma factor sigma A. crsA mutations are known to restore sporulation in certain spo0 mutants. crsA suppression of kinA and ftsA mutations was achieved through inhibition of the transcription of sin, a gene involved in the selection between several post-exponential-phase cell states. A deletion of sin restored sporulation competence in spoIIF, spoIIJ, or spoIIN mutant strains. A sin deletion was also able to restore sporulation competence in the crsA suppressible stage 0 mutant spo0K141.

Bacillus subtilis↗

PubMed1990

Isolation and characterization of Bacillus stearothermophilus 30S and 50S ribosomal protein mutations.

Bacillus stearothermophilus mutations which confer resistance to or dependence on a variety of ribosome-targeted antibiotics have been isolated. Many of these mutations produce ribosomal proteins with altered mobilities in a two-dimensional gel electrophoresis system. This collection of altered thermophilic ribosomal proteins will be useful in examining ribosomal structure and function.

Bacterial Proteins↗

PubMed1989

The distribution of mutagenic activity in red, rose and white wines.

Using a modified Salmonella typhimurium TA98 Ames-test system, more than 150 red, white and rose wines were analyzed for direct-acting and microsomal enzyme-enhanced mutagenic activity. The following conclusions were reached from analysis of this wine mutagenicity data base. White and rose wines, as well as grape juices, exhibited little or no detectable direct-acting or microsomal enzyme-enhanced mutagenic activity. However, red wine samples contained highly variable amounts of mutagens, ranging from undetectable to levels 30-fold above the sensitivity limit of the assay system. The variations in red wine mutagenicity were unrelated to grape variety, vintage, aging methods or production region. Hence, individual winery production practices must represent the most significant contribution to the variations observed.

Biotransformation↗

PubMedDate not supplied

Suppression of defective-sporulation phenotypes by mutations in transcription factor genes of Bacillus subtilis.

Mutations in the Bacillus subtilis major RNA polymerase sigma factor gene (rpoD/crsA47) and a sensory receiver gene (spoOA/rvtA11) are potent intergenic suppressors of several stage 0 sporulation mutations (spoOB, OE, OF & OK). We show here that these suppressors also rescue temperature-sensitive sporulation phenotypes (Spots) caused by mutations in RNA polymerase, ribosomal protein, and protein synthesis elongation factor EF-G genes. The effects of the crsA and rvtA suppressors on RNA polymerase and ribosomal protein spots mutations are similar to those previously described for mutations in another intergenic suppressor gene rev. We have examined the effects of rvtA and crsA mutations on the expression of sporulation-associated membrane proteins, including flagellin and penicillin binding protein 5* (PBP 5*). Both suppressors restored sporulation and synthesis of PBP 5* in several spoO mutants. However, only rvtA restored flagellin synthesis in spoO suppressed backgrounds. The membrane protein phenotypes resulting from the presence of crsA or rvtA suppressors in spoO strains suggests that these suppressors function via distinct molecular mechanisms. The rvtA and crsA mutations are also able to block the ability of ethanol to induce spoO phenocopies at concentrations of ethanol which prevent sporulation in wild type cells. The effects of ethanol on sporulation-associated membrane protein synthesis in wild type and suppressor containing strains have been examined.

Bacillus subtilis↗

PubMedDate not supplied

Intergenic suppression of stage II sporulation defects by a mutation in the major vegetative sigma factor gene (rpoD) of Bacillus subtilis.

The Bacillus subtilis intergenic suppressor mutations crsA and rvtA, previously shown to restore sporulation competence to a variety of strains containing stage 0 sporulation defects, also suppress lesions in the stage II sporulation genes spoIIF, spoIIN and spoIIJ. They do not rescue sporulation in other stage II through stage V sporulation mutations. Cells containing spoIIN, spoIIF96 and spoIIJ::Tn917 mutations fail to transcribe spoIID, a late stage II gene. Introduction of crsA47 into spoIINts279, spoIIF96, or spoIIJ::Tn917 mutant backgrounds circumvents the need for the spoIIF, IIN, and IIJ products, restoring both expression of spoIID, and sporulation competence.

Bacillus subtilis↗