Table 1.

Yeast strains used in this work

Strain	Genotype	Origin
W303	MATa ade2-1 ura3-1 his3-11,15 trp1Δ63 leu2-3,112 can1-100	E. Elion (24), Harvard Medical School
QBY51	MATa ade6 lys1 [ρ°]	This work
QBY52	MATα ade6 lys1 [ρ°]	This work
QBY274	MATα ade2-1 ura3-1 his3-11,15 trp1Δ63 leu2-3,112 can1-100 kar1Δ15	This work
QBY276	MATa ade2-1 ura3-1 his3-11,15 trp1Δ63 leu2-3,112 can1-100 msl1Δ∷HIS3	This work
QBY320	MATa ade2-1 ura3-1 his3-11,15 trp1Δ63 leu2-3,112 can1-100 msl1Δ∷HIS3 [ρ+] (pQB223)	This work
HM402	MATα ade2-1 his3-11,15 leu2-3,112 trp1-1 ura3-1 can1-100 nam2Δ∷LEU2 [Δ introns]	C. Herbert (11), CNRS-Gif-sur-Yvette
HM410	MATα ade2-1 his3-11,15 leu2-3,112 trp1-1 ura3-1 can1-100 nam2Δ∷LEU2 [wt 777-3A*]	C. Herbert (11), CNRS-Gif-sur-Yvette
HM411	MATα ade2-1 his3-11,15 leu2-3,112 trp1-1 ura3-1 can1-100 nam2Δ∷LEU2 [box7 mutant (V328)†]	C. Herbert (11), CNRS-Gif-sur-Yvette
S912/50	MATa his4 NAM2-1 [ρ°]	C. Herbert (11), CNRS-Gif-sur-Yvette

CNRS, Centre National de la Recherche Scientifique. 

^*Strain 777-3A contains a cob gene with five introns including the bI4 intron (49). 

^† The box7 mutant at site V328 is located in the ORF encoding the bI4 maturase and inactivates maturase function (50).