Northwestern blot

Western Blotting A method for identifying proteins after electrophoretic separation involving a specific probe, usually an antibody. It was derived from the earlier development of southern blotting and northern blotting. See also Northwestern Blotting, Southwestern Blotting. See Radka, S.P., Monoclonal... 

Two dimensional (2D) Northwestern blotting complements gel-shift experiments in the identification of specific protein-nucleic acid interactions. The procedures described below, which have been adapted from the protocol described by Schenkel et al. (1988), have been valuable in our laboratory for the identification of several hnRNP proteins (our unpublished observations). Here, we demonstrate the technique on 2D gel blots of transformed human amnion (AMA) cell proteins (Fig. 1) using poly(rC), a homopolymer that interacts with hnRNPs K and L (Matunis et al., 1992 Dejgaard et al., 1994), as well as poly(rU), which interact with hnRNPs C and M (Swanson and Dreyfuss, 1988 Dreyfuss et al., 1993). The technique works equally well, however, when sequence-specific deoxyoligonucleotides are used as probes. 

FIGURE 1 Incubation of a Northwestern blot in an hybridization oven. 

---