Q system

The Q system is an expression system similar in principle to the GAL4/UAS system but based on genes from the Neurosporacrassa qa cluster.  It is composed of two regulatory proteins (QF and QS) and a binding site for QF called QUAS (QF upstream activating sequences). QF is a transcriptional regulator that binds to QUAS sequences and transcriptionally activates downstream genes.  QS is a QF repressor that effectively blocks QF-mediated transcriptional activation.  QS repression of QF can be suppressed by quinic acid.  QF-based MARCM can be used independently or in conjunction with GAL4-based MARCM to refine and expand the range of expression patterns available via GAL4-based expression alone.

Primary reference: Potter, et. al. 2010

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HACKed QF2 Stocks

Lin and Potter (2016) developed the homology assisted CRISPR knock-in (HACK) method and applied this method to convert commonly-used GAL4 lines into QF2-expressing lines.  More information on these stocks can be found on our HACK page.