Top: Conserved motifs with specific intrinsic functions shared by GRTH with members of the DEAD-box family of proteins are indicated as (Q, I, Ia, Ib and II–VI). Amino acid position of each motif is indicated. Below: Summary of specific physiological function of GRTH. (Tang, et al., 1999, Sheng, et al., 2003, Sheng, et al., 2006).