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p107 protein complexes in early 3T3‐L1 pre‐adipocyte differentiation
Author(s) -
Hayes Timothy E,
Ngwanyam Remy Royeh,
Spore Joshua,
Opitz Sarah,
Barham Jonathan
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a545-d
Subject(s) - immunoprecipitation , stimulation , chemistry , microbiology and biotechnology , biology , endocrinology , gene , biochemistry
Quiescent 3T3L1 cells express Rb family member p130 but little p107. After stimulation to differentiate p130 levels rapidly decline while p107 rises dramatically. The levels of p130 and p107 revert as the cells complete differentiation. Interference with the increase in p107 expression blocks differentiation. The goal of this study is to determine the mechanism of p107 action in 3T3‐L1 differentiation. We have reanalyzed published microarray data from differentiating and differentiation‐inhibited 3T3‐L1s for the expression patterns of 113 Rb family binding proteins and found at least 9 that are good candidates for interaction with p107. Column chromatography of 3T3‐L1 nuclear extracts shows that p107 divides into 2 distinct fractions by size with 25–50% in the larger peak. EMSA analysis shows that one or more E2Fs complex with p107. Immunoprecipitation analysis shows that p107 and p130 share some binding partners, such as E2F4, but not others. Since the increase in p107 is critical for differentiation, proteins that interact with p107 but not p130 may be the link between p107 and its effect on differentiation. This work was supported by NIH Grant P20 RR‐16460 from the INBRE program of NCRR