Specific oligobodies against ERK-2 that recognize both the native and the denatured state of the protein

Oligonucleotide aptamer(s), obtained by using the SELEX procedure, has been used as reagents to recognize different molecules with high affinity and s pecificity. However, until recently, it was not possible to obtain oligonuc leotide-based reagents able to recognize proteins with high specificity in assays typical of antibodies, such as immunohistochemistry, Western blottin g and immunsprecipitations. Here, we show the results obtained by applying the strategy of "target switching" to obtain specific polyclonal and monocl onal oligobodies against the protein ERK2. We were able to develop highly s pecific polyclonal oligobodies by using only one selection step with a temp orary target and one selection step with the final target (ERK2). Since onl y two selection steps were required, these results demonstrate that it is p ossible to obtain specific reagents against a protein without a need for an "in vitro evolution" using many selection steps, or error-prone polymerase s. After one additional selection step, the polyclonal oligobodies were clo ned to obtain a highly specific monoclonal oligobody. (C) 2001 Elsevier Sci ence B.V. All rights reserved.