Franz Wohlrab

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The extracellular matrix surrounding vertebrate oocytes is called the zona pellucida in mammals and perivitelline membrane (pvm) in birds. We have analyzed this structure in chicken follicles and laid eggs and have identified a 95-kDa component of the pvm, which, by protein sequencing, shows homology to mammalian zona pellucida proteins. Surprisingly, we(More)
The avian perivitelline membrane (PVM) is the site of initial contact between sperm and egg. It consists of only two major components, which are both homologues of the mammalian zona pellucida (ZP) proteins, and belong to the ZP1 and ZPC families, respectively. We have established a method to isolate large quantities of both native avian ZP proteins and(More)
A family of unusual DNA structures has been discovered in segments with predominantly purines in one strand (pur.pyr sequences). These sequences are overrepresented in eukaryotic DNA and have been mapped near genes and recombination hot spots. When cloned into recombinant plasmids, many pur.pyr sequences are reactive to chemical and enzymic probes that are(More)
Nuclei from baby hamster kidney cells infected with herpes simplex virus type 1 contain a virus-specific deoxyribonucleoside triphosphate degrading activity. The reaction proceeds at 4 degrees C and can thus be distinguished from host enzymes. Under these conditions the enzyme is specific for deoxyribopyrimide triphosphates and catalyzes pyrophosphate(More)
The interaction of chicken spermatozoa with the inner perivitelline layer from different avian species in vitro during a 5 min co-incubation was measured as the number of points of hydrolysis produced per unit area of inner perivitelline layer. The average degree of interaction, as a proportion of that between chicken spermatozoa and their homologous inner(More)
Infection of cells with herpes simplex virus type 1 (HSV-1) induces high levels of deoxypyrimidine triphosphatase. The majority of the enzyme activity is found in infected cell nuclei. A similar activity is induced by HSV type 2 (HSV-2) which, in contrast to the HSV-1 enzyme, fractionates to more than 99% in the soluble cytoplasmic extract. Of a series of(More)
The substrate specificity of 2'-deoxy-2'-substituted uridines and their 5'-phosphates towards thymidylate synthetase from Escherichia coli K12 was investigated. Besides the natural substrate 2'-deoxyuridine-5'-phosphate (dUMP), only 2'-deoxy-2'-fluorouridine-5'-phosphate (dUflMP) was a substrate. The KM of dUflMP is 11 times higher than that of dUMP, while(More)
The 12-base pair (bp) tandem direct repeat sequences (DR2) at the joint region (a sequence) of herpes simplex virus type 1 (strain F) adopt a new type of DNA conformation under the influence of negative supercoiling. The novel conformation is dependent on the number of the DR2 repeats; the 19 mer (228 bp total) and the 14 mer (168 bp) readily form the(More)
In a blind study, 21 clinical isolates of herpes simplex virus which had been typed using differential growth on guinea pig embryo versus chicken embryo cells were tested for the presence of the viral deoxyribopyrimidine triphosphatase. In all isolates of type 1, the triphosphatase was present in the nuclei of the infected cells, while none of the HSV-2(More)
In conclusion, one of the aspects of the DNA polymorphism observed is the formation of Z-DNA under a variety of conditions. Left-handed DNA stretches not only represent alternate structures, but also exert long-range effects due to their influence on superhelical properties on an entire supercoiled DNA as first shown six years ago [49, 50]. The examples(More)