Figure 1.

Schematic representation of the hPop1, Rpp38, and hPop4 proteins. The length, putative nuclear localization signals (NLS) and nucleolar localization signals (NoLSs) as established by Jarrous and coworkers (Jarrous et al., 1999b) for the hPop1 (A), Rpp38 (B), and hPop4 (C) protein subunits are depicted in the upper parts. The lower parts represent charge plots of these proteins. Values on the vertical axis represent positively charged and negatively charged regions, respectively. These values were calculated with the use of a window of nine amino acids. Gray regions in the charge plots represent the regions of the proteins important for their nucleolar localization. For the hPop1 protein (A) the charge plot of only amino acids 100–400 is depicted (hatched area in upper part). The R-, W- and G-box refer to conserved sequence elements observed in the hPop1 protein (Lygerou et al., 1996b).