The authors and journal apologise for an error in the above paper, which appeared in volume 224 part 3, pages R139–R159. The error relates to the legend to Figure 2 on page R141.
The original legend to Figure 2 on page R141 stated ‘(A) The primary transcript is synthesized in the nucleus as prepro-TRH heterogeneous nuclear RNA (hnRNA) which contains two introns and five exons’. The correct legend should read ‘(A) The primary transcript is synthesized in the nucleus as prepro-TRH heterogeneous nuclear RNA (hnRNA) which contains two introns and three exons’. The correct Figure 2 is published in full below: