FIG. 6.

Model of RNA-protein interactions affecting RNP assembly and remodeling during RNA localization. (A) RNP assembly initiates in the nucleus, and during the early steps in the vegetal RNA localization pathway, PTB/hnRNP I (orange ovals) and potentially other nuclear factors (gray squares) are bound directly to VLE RNA sequences. Vg1RBP/vera (green triangles) is associated only indirectly with VLE RNA, through protein-protein interactions. The RNP is remodeled at later times during the vegetal RNA localization pathway, such that Vg1RBP/vera binds directly to VLE RNA. (B) VLE RNA transcripts containing mutations within VM1 sites cannot bind either directly or indirectly to PTB/hnRNP I. VM1 mutant VLE RNA transcripts bind Vg1RBP/vera (green triangles) indirectly, through protein-protein interactions, but remodeling of the RNP to allow direct interaction between Vg1RBP/vera and VLE RNA is blocked, as is vegetal RNA localization.