Table II. Effect of ccr4 alleles on mRNA half-lives.

Alleles	mRNA half-lives (min)
	ADH2	HSPn12	GAL1
CCR4	11	9	8.0
ccr4-1 (E556A)	16	12	11
ccr4-2 (D713A)	17	20	13
ccr4-3 (D780A)	15	13	10
ccr4-4 (H808A)	11	13	13
ccr4	19	13	12

Strains are the same as described in Table I. mRNA half-lives were determined in the single-copy MD9-7c strains by quantitative S1 nuclease protection assays. RNA was extracted for times up to 40 min from yeast pre-grown for 3 h on YEP medium containing 2% glycerol/20% ethanol for ADH2 and HSP12, and 2% galactose/2% raffinose for GAL1 that was shifted to fresh medium containing 8% glucose. For the GAL1 determination, the standard errors of the mean were <5% for CCR4, 10% for ccr4-3 and 15–20% for the other alleles. For ADH2 and HSP12, the standard errors of the mean were <10% for all alleles, with the exception of <20% for ccr4-2 (ADH2) and ccr4-3 (ADH2), and <30% for ccr4-2 (HSP12).