Biomedical subjects

H C Kaerner

Publications and source records attributed to H C Kaerner.

32 records · Page 2Linked to original sources

PubMed1981

Amplification of a short nucleotide sequence in the repeat units of defective herpes simplex virus type 1 Angelotti DNA.

It has been shown earlier that the reiterated regions TRS and IRS bracketing the Us segment of herpes simplex virus type 1 Angelotti DNA are heterogeneous in size by stepwise insertion of one to six copies of a 550-base-pair nucleotide sequence. Considerably higher amplification of this sequence was observed in defective viral DNA: up to 14 copies were detected to be inserted in the repeat units of a major class of defective herpes simplex virus type 1 Angelotti DNA, dDNA1, which originated from noncontiguous sites located in UL and the inverted repeats of the S component of the parental genome. Physical maps were established for the cleavage sites of KpnI, PstI, XhoI, and BamHI restriction endonucleases on the repeats of dDNA1. The map position of the insertion sequence was determined. It was demonstrated that the amplified inserts were not distributed at random among or within the repeats. A given total population of dDNA1 molecules consisted of different homopolymers, each of which contained a constant number of inserts in all of its repeats. Assuming that a rolling-circle mechanism is involved in the generation of full-length defective herpes simplex virus type 1 Angelotti DNA from single repeat units, these data suggest that the 550-base-pair sequence is amplified in the repeats before the replication process.

DNA Replication↗

PubMed1980

Virus-specific basic phosphoproteins associated with herpes simplex virus type a (HSV-1) particles and the chromatin of HSV-1-infected cells.

Herpes simplex type 1 Angelotti (HSV-1 ANG) virions were shown to contain two major acid-soluble proteins, BP1 and 2, which by size and charge analysis were also found to be associated with chromatin isolated from HSV-1 ANG-infected African green monkey kidney cells (HSV-chromatin). BP1 and 2 proved to exist in a phosphorylated state both in virions and in HSV-chromatin. BP1 consisted of a single polypeptide of 38 K mol. wt. which was correlated to the tegument protein VP22. In SDS-polyacrylamide gels BP2 migrated as a single polypeptide band with an apparent mol. wt. of 12 K. Urea gel analysis revealed that BP2 consisted of three components, BP2a, b and c, of different phosphate contents. Arguments were provided that these components probably represent different polypeptides of similar mol. wt. HSV-chromatin, in addition to BP1, BP2a, b and c contained a further major virus-induced basic phosphopolypeptide of mol. wt. 65 K which was not detected in acid-extracts of mature virions.

Animals↗

PubMed1979

Origin of two different classes of defective HSV-1 Angelotti DNA.

During serial passages of Herpes simplex virus (HSV) at high multiplicity of infection, virions containing defective viral DNA accumulate in the progeny. The defective DNA molecules are made up by repeats of restricted portions of the standard viral genome. Two different classes of defective DNA derived from HSV-1 Angelotti (ANG) in independent series of high MOI-passages were studied. The nucleotide sequences contained in the defective DNA were localized on the parental viral genome. One of the two classes contained sequences from non-contiguous sites mapping in unique and in redundant regions of the parental DNA, whereas the second class apparently originates from the S-terminal redundant region of the parental DNA. The localization of defective DNA sequences was complicated by the fact that there exists sequence homology between the S-terminal redundancy and various unique DNA sequences in the L-segment of the HSV-1 ANG genome.

Base Sequence↗

PubMed1979

Herpes simplex virus type 1 Angelotti and a defective viral genotype: analysis of genome structures and genetic relatedness by DNA-DNA reassociation kinetics.

DNA-DNA reassociation kinetics of herpes simplex virus type 1 Angelotti DNA and a class of defective viral DNA revealed that the viral standard genome has a total sequence complexity of about 93 X 10(6) daltons and that a portion of 11 X 10(6) daltons occurs twice on the viral genome. These results agree with structural features of herpes simplex virus type 1 DNA derived from electron microscopic studies and restriction enzyme analyses by several investigators. The defective viral DNA (molecular weight, about 97 X 10(6)) displays a sequence complexity of about 11 X 10(6) daltons, suggesting that the molecule is built up by repetitions of standard DNA sequences comprising about 15,000 base pairs. A 2 X 10(6)-dalton portion of these sequences maps in the redundant region and a 9 X 10(6)-dalton portion maps in the unique part of the standard herpes simplex virus type 1 Angelotti DNA, as could be shown by reassociation of viral standard DNA in the presence of defective DNA and vice versa. No cellular DNA sequences could be detected in defective DNA. A 12% molar fraction of the defective DNA consists of highly repetitive sequences of about 350 to 500 base pairs in length.

Base Sequence↗

PubMed1977

In vitro transcription of herpes simplex virus ANG DNA by E-coli RNA polymerase.

HSV-1 ANG DNA and a defective genome of the same virus were transcribed with E. coli RNA polymerase under various salt conditions. The extent of transcription was assayed by hybridizing the cRNA to the Hind III, Hpa I and Hind II restriction fragments of the DNA templates using the blot technique of E. Southern. The transcripts proved to contain sequences homologous to all DNA fragments. A similar ratio of hybridized cRNA and the amount of fragment DNA was observed in all cases. The results suggest that both, the wt and the defective HSV ANG genome were completely transcribed.

Cell-Free System↗

PubMed1977

Morphological transformation of rat embryonic fibroblasts by abortive herpes simplex virus infection: increased transformation rate correlated to a defective viral genotype.

Rat embryo fibroblasts were abortively infected with various stocks of herpes simplex virus type 1 strain ANG at 42 degrees. In uninfected controls all of the cells died during an 8-day incubation period at the elevated temperature, whereas varying numbers of cells in the infected cultures survived and formed colonies during subsequent incubation for 3--4 weeks at 37 degrees. All of the survivors appeared to be morphologically transformed. Two types of survivors, epithelial- and spindle-like cells, which occurred at a ratio of approximately 1:1 in all assays, could be distinguished. The observed survival rates increased from about 1 x 10-7 to 3 x 10-5, corresponding to increasing fractions (0--50%) of a defective genotype present in the infecting virus stocks. The individual survival rates do not depend exclusively on the quantity of defective virions. The existence of different subtypes of defective genomes as a further parameter is discussed.

Animals↗

PubMed1976