Circulating a,-antitrypsin is synthesized primarily in the liver and secreted into the bloodstream, where it serves as the major protease inhibitor. The PiZ variant of a1-antitrypsin is associated with decreased levels of the protein in sera as a result of its retention within hepatocytes. Homozygosity for the variant allele predisposes individuals to the development of pulmonary emphysema and an increased risk for liver disease. We and others have previously demonstrated that the normal PiM human a,-antitrypsin gene can be properly expressed in the livers of transgenic mice. The PiZ variant of the human a,-antitrypsin gene was introduced into the germline of mice to determine whether the mutant protein would accumulate in mouse hepatocytes and if such accumulation would result in the development of liver damage in an animal model. As expected, the mutant human protein was abundantly synthesized in the livers of the transgenic animals and accumulated within the rough endoplasmic reticulum of hepatocytes as it does in human patients. PiZ mice developed significantly more liver necrosis and inflammation than PiM transgenic mice or control littermates. The degree of liver damage was correlated with the amount of PiZ a,-antitrypsin accumulated in the liver of the different pedigrees of mice. Although 40% of PiZ mice tested were seropositive for mouse hepatitis virus (MHV), the degree of liver damage was not influenced by the MHV seropositivity; rather, it was related only to the presence of accumulated PiZ protein.

Chromosomal position effects can influence strongly the transcription of foreign genes in transgenic animals. This results in low frequencies and levels of gene expression and, in some cases, in aberrant patterns of expression. Strategies for overcoming these effects are described with particular reference to their application in embryonic stem cells.

Normal and mutant human alpha-1-antitrypsin genes were cloned from a PiMZ heterozygous individual. Nucleotide sequence comparison demonstrated a T to C transition in exon III and an G to A transition in exon V of the PiZ gene. A 14.4 kb DNA fragment containing the entire PiM gene plus 2 kb of 5' and 3' flanking genomic DNA sequences was introduced into the germ line of mice and five F0 transgenic lines were established. Transgenic F1 progeny from F0 parents exhibited high levels of human alpha-1-antitrypsin protein in their plasma. The human gene was expressed primarily in liver of the transgenic mice as it is in man. However, expression of the human alpha-1-antitrypsin gene was also observed in kidneys of the transgenic mice, which led to the observation that the endogenous mouse gene is also expressed in the kidney. These data indicate that cis-acting elements within or proximal to the human alpha-1-antitrypsin gene are able to direct its in vivo transcription with a high degree of tissue specificity.

The Argentine stem weevil, Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae), is an important introduced pasture pest in New Zealand. In this study geographical populations of this species were analysed using polymerase chain reaction-based randomly amplified polymorphic DNA (RAPD), in an attempt to determine the geographical origin of the pest. Morphologically indistinguishable individuals were collected from nine South American, five New Zealand and one Australian populations. Ten primers were screened for usefulness, two of which revealed significant, scorable polymorphisms between these populations. The results indicated that the sampled New Zealand L. bonariensis populations originated from the east coast of South America.

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