tokens: In strains lacking tup11 and tup12 , the atf1-pcr1 transcriptional activator continues to play a central role in fbp1-lacZ expression ; however , spc1 MAPK phosphorylation of atf1 is no longer essential for its activation .
folded_tokens: in strain lack tup11 and tup12 , the atf1-pcr1 transcriptional activator continue to play a central role in fbp1-lacz expression ; however , spc1 mapk phosphorylation of atf1 be no longer essential for its activation .