Isolation and complete nucleotide sequence of the gene for bovine parathyroid hormone

The structure of the bovine parathyroid hormone (PTH) gene has been analyzed by Southern blot hybridization of genomic DNA and by nucleotide sequence analysis of a cloned PTH gene. In the Southern analysis, several restriction enzymes produced single fragments that hybridized to PTH cDNA suggesting that there is a single bovine PTH gene. The restriction map of the cloned gene is the same as that determined by Southern blot analysis of bovine DNA. The sequence of 3154 bp of the cloned gene has been determined including 510 bp and 139 bp in the 5' and 3' flanking regions, respectively. The gene contains two introns which separate three exons that code primarily for: (i) the 5' untranslated region, (ii) the pre-sequence of preProPTH, and (iii) PTH and the 3' untranslated region. The gene contains 68% A + T and unusually long stretches of 100- to 150-bp sequences containing alternating A and T nucleotides in the 5' flanking region and intron A. The 5' flanking region contains two TATA sequences, both of which appear to be functional as determined by S1 nuclease mapping. Compared to the rat and human genes, the locations of the introns are identical but the sizes differ. Comparable human and bovine sequences in the flanking regions and introns are about 80% homologous.     

Molecular and cytological characteristics of nuclear DNA and chromatin for angiosperm systematics: DNA diversification in the evolution of four orchids

The species- and genus-specific DNA content, average base composition of nuclear DNA, presence or absence of satellite DNA, the percentage of heterochromatin and other characteristics of nuclear DNA and nuclear structure allow to deduce the molecular changes which accompanied, or more probably caused, cladogenesis in the orchids studied. It is suggested that saltatory replication (generative amplification) of certain DNA sequenes, diversification of reiterated DNA sequences, and loss of DNA play an important role in the evolution of orchids.—The relationship between changes of genome composition and of nuclear structure and ultrastructure is discussed on the basis of cot curves, heterochromatin staining with Giemsa (C banding), electron microscopy of nuclei, and molecular hybridization in situ.Some aspects of this paper have been presented at the Helsinki Chromosome Conference, August 1977 (Nagl & Capesius 1977).     

In vitro construction of a recombinant adenovirus Ad2:Ad5

A hybrid virus containing the left half of the Ad5 genome and the right half of the Ad2 genome has been constructed by ligating together in vitro the BamHI.-A fragment of Ad5 (map co-ordinates 0–59.5) to the-SawHI-A fragment of Ad2 (map coordinates 59.5–100), and using this DNA to transfect susceptible cells. Viable progeny virus has been obtained which grows as well as the parental virus without any requirement for helper virus, and probably contains a hybrid hexon polypeptide consisting of the major part of the Ad5 hexon with an Ad2 carboxy terminus.     

Recombination between satellite phage P4 and its helper P2. I. In vivo and in vitro construction of P4: :P2 hybrid satellite phage

P4::P2 hybrid satellite phages which carry a portion (including the P2 head gene Q and the cohesive end) of the left end of the P2 chromosome linked to the essential part of the P4 chromosome have been isolated by in vivo as well as in vitro recombination. These hybrids express gene Q and grow in the presence of a P2 helper even if defective in gene Q.     

Construction of plasmids that produce phage P22 repressor

In a series of plasmid constructions, the c2 (repressor) gene of phage P22 was cloned in a multicopy plasmid and expressed at increasing level. The final result of these constructions is a plasmid that maintains a level of approx. 200 times as much repressor as is found in a lysogen. A series of increasingly virulent phage mutants was isolated by plating sequentially on host cells with increasing levels of repressor. The methods used in the constructions should be applicable to obtaining elevated expression of cloned genes in other systems.