FIG. 6.

NRCs form homodimers in vivo and in vitro. (A) LexA-rNRC.1 was transformed into yeast along with pJG4-5, which expresses rNRC.1 as a B42 fusion protein (B42-rNRC.1). pJG4-5 (B42) and pEG202 (LexA), pJG4-5 (B42) and LexA-rNRC.1, and B42-rNRC.1 and pEG202 (LexA) were also transformed into yeast and served as controls. Similar studies were carried out with hNRC(771-1076) cloned into LexA and B42 expression vectors. (B) GST-rNRC.1 or GST alone was incubated with ³⁵S-rNRC.1 labeled with l-[³⁵S]methionine in rabbit reticulocyte lysates, and in vitro binding was carried out as described in Materials and Methods. The samples were then electrophoresed in SDS gels, and the amount of ³⁵S-rNRC.1 which bound to GST-rNRC.1 was visualized by fluorography. One-tenth of the input amount of ³⁵S-labeled rNRC.1 used in the incubation with GST-rNRC.1 was electrophoresed in the same gel.