TABLE 3

[ PSI+] variants induced in the presence of different [ PIN+] variants

No. of [ PSI+ ] colonies
StrongWeakUnstableMixed
[PIN+]% [PSI+][ PIN+][ pin][ PIN+][ pin][ PIN+][ pin][ PIN+][ pin]
Low s.d.2.63500027a030
Medium s.d.6.6102301518a021
High m.d.12.42802500090
Very high s.d.35.0291724b00000

Sup35 was overproduced in four different 74-D694 [PIN+] derivatives (see materials and methods). The percentage of [PSI+] is equal to the non-red colonies divided by ~7000 (low), 2400 (medium), 2400 (high), and 1200 (very high) total colonies. Approximately 70 colonies from each derivative were scored as strong, weak, or unstable [ PSI+]. Some colonies were scored as mixed because their three to six descendent colonies displayed a nonhomogenous combination of the [ PSI+] states normally induced in that derivative. One explanation for the mixed events is that clumps of cells (more than two) were independently induced to different [PSI+] states and formed a colony. Colonies were also scored for [PIN+].

  • a Of 27 unstable [ PSI+] induced in cells containing low s.d. [ PIN+], 17 were extremely unstable and 10 were slightly unstable. In medium s.d. [PIN+], 17 of 18 induced were extremely unstable and one was slightly unstable.

  • b Of 24 weak [ PSI+] induced in the presence of very high [ PIN+], 23 were unusual in that they frequently converted to strong [PSI+] (see text).