Heterologous CpG island becomes extensively methylated in the genome of transgenic mice.

It is demonstrated that a heterologous (chicken) CpG island containing five Sp1 canonical recognition sequences becomes highly methylated in the genome of transgenic mice bearing one or several copies of the transgene. Similar levels of methylation of the chicken CpG island were observed in different tissues of transgenic mice except the brain where the level of methylation of this chicken CpG-rich fragment was significantly lower than in other tissues. Analysis of susceptibility of the "transgenic" CpG island to Hpa II and Msp I restriction nucleases revealed an unusual methylation pattern interfering with the action of both of these enzymes.

[New approaches to construction of transgenic animals with high level tissue-specific expression of foreign genes: construction and reconstruction of genomic domains].

The major problems in constructing transgenic animals and approaches to their solution are discussed. Modern views of the structural-functional organization of the eukaryotic genome are considered. The domain hypothesis of the genome organization is analyzed in detail, as many problems associated with a low level and a lack of tissue specificity of transgene expression can be solved at the step of construction (or reconstruction of existing domains).

Mapping of replication origins and termination sites in the Duchenne muscular dystrophy gene.

The replication structure of the human dystrophin gene in cultured masculine erythroleukemia cells (line HEL 92.1.7) was studied using the replication direction assay.