Using Transactivation Lines
Researchers and those who are attempting to develop traits that involve multiple genes in a pathway may prefer to use the transcription factor and upstream activation sequence (UAS) cassettes (for example pTNTQ60 and pTNTQ61.3) in separate plant lines that can be crossed.
There are a variety of reasons for doing this. One of the most powerful is that multiple genes can be constructed with the same UAS, and whether they are transformed or crossed in simultaneously or at different times, they can be coordinately regulated by a single transcription factor that is transformed or crossed in separately.
This strategy may be useful to explore gene functions or identify potentially useful promoters using a line that contains a new transcription factor insertion ("transactivation line") without altering genetic expression in that line. In such instances the cross could be made to any line with an upstream activation sequence (UAS) coupled to a reporter gene such as GUSPlus.
Sexually crossing a transactivation line with a UAS 'Gene X' line may also be advantageous when researchers are endeavoring to create a large number of diverse offspring.
Crossing in this way, described in CAMBIA's published patent application WO 01/21785, may be necessary to circumvent constraints in certain jurisdictions on certain patented promoters, that prevent the activation of a promoter by a binding molecule transformed into the same plant.
Where such patent constraints are not in force, obtaining coordinate expression of unlinked genes could also be accomplished by co-transformation with the artificial transcription factor encoded by pTNT.Q.61.3 and constructs containing any genes regulated by the UAS cassette of pTNT.Q.60, or by subsequent transformations of a line already containing the artificial transcription factor encoded by pTNT.Q.61.3.
Full sequences and diagrams of these constructs are available on a page visible to all who have executed a BiOS license. (Anyone else wishing information may write to cambia@cambia.org).
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