A CONSTRUCT CAPABLE OF RELEASE IN CLOSED CIRCULAR FORM FROM A LARGER NUCLEOTIDE SEQUENCE PERMITTING SITE SPECIFIC EXPRESSION AND/OR DEVELOPMENTALLY REGULATED EXPRESSION OF SELECTED GENETIC SEQUENCES

摘要

The present invention relates generally to constructs and in particular genetic constructs comprising polynucleotide sequences capable of release in covalently closed, circular form from a larger nucleotide sequence such as, but not limited to, a genome of a eukaryotic cell. Preferably, once released , a polynucleotide sequence is reconstituted in a form which permits expressio n of the polynucleotide sequence. In one embodiment, the reconstituted polynucleotide sequence comprises a coding sequence with all or part of an extraneous nucleotide such as, but not limited to, intronic sequence or othe r splice signal inserted therein. Expression and in particular transcription o f the coding sequence involves splicing out the extraneous sequence. The relea se and circularization is generally in response to a stimulus such as a protein - mediated stimulus. More particularly, the protein is a viral or prokaryotic or eukaryotic derived protein or developmentally and/or tissue specific regulat ed protein. The construct of the present invention is particularly useful in conferring genetic resistance against pathogens or inducing apoptosis or oth er cell death mechanisms useful, for example, in treating cancer or inducing ma le or female sterility in plants. The constructs permit, therefore, site specif ic expression and/or developmentally regulated expression of selected genetic sequences.