<i>In vitro</i> titan cells generation is dependent on the negative regulator <i>PKR1</i> and <i>TSP2</i>.

<p><b><i>(A)</i></b><i>PKR1</i> is a repressor of titan cells formation in KN99α background and (<b>B</b>) in H99 background. (<b>C</b>) in galactose mimimal medium (galactose MM), GAL7 promoter upstream of the <i>PKA1</i> and <i>PKR1</i> genes induced an increased titan cells formation for PKA1 and a decreased titan cells formation for PKR1 (<b>D</b>) In minimal medium with glucose (glucose MM)), GAL7 promoter induced a repression of titan cells formation for PKA1 and an induction of titan cells formation for PKR1. (<b>E</b>) Tetraspanin 2 (<i>TSP2</i>) is a repressor of titan cells formation. Complementation of the deletion mutants restored the phenotype of KN99α. The ratio to H99 or KN99α, used as a calibrator in each experiment, was calculated for each strain (panel A to E) and results expressed as mean ± SD. Experiments A to G were done in triplicate. To compare the experimental conditions to H99O, Khi2 analysis was performed (*p<0.0001 vs control H99 or KN99α or appropriate mutants).