Figure 4.

Insufficient poly(A) shortening in HeLa cells expressing phospho-mimic CNOT2.

(A) HeLa cells were infected with retrovirus expressing mock (-) or the indicated CNOT2 constructs (WT, SA, or SE). They were subsequently transfected with control siRNA or siRNA against CNOT2. Lysates were prepared from these cells and analysed by immunoblot. Lower bands indicated by an arrowhead and upper bands indicated by an asterisk correspond to endogenous CNOT2 and exogenously expressed HA-tagged CNOT2, respectively (the top panel). (B) Total RNA was prepared from cells shown in (A). Poly(A) tail lengths of mRNAs were analysed using the extracted total RNA (see the Materials and Methods). (C) HeLa cells were pretreated with (+) or without p38MAPK inhibitor (-) for 30 min. Subsequently, cells were treated with (+) or without sorbitol (-) for 30 min. Poly(A) tail lengths of mRNAs were analysed as in (B).