Project description:In order to identify mechanisms of drug resistance to HER2-targeted therapy, we performed cDNA microarray analysis on drug naiive BT474 and drug resistant BT474 cells treated with lapatinib for 0, 10, and 20 hrs.
Project description:To identify mechanisms that regulate V(D)J recombination, we used proximity-dependent biotin identification to analyze the interactomes of full length and truncated forms of RAG1 in pre-B cells. This revealed an association of RAG1 with numerous nucleolar proteins in a manner dependent on amino acids 216-383 and allowed identification of a motif required for nucleolar localization. Experiments in transformed pre-B cell lines and cultured primary pre-B cells reveal a strong correlation between disruption of nucleoli, reduced association of RAG1 with a nucleolar marker, and increases in V(D)J recombination activity. Mutation of the RAG1 nucleolar localization motif boosts recombination while removal of the first 215 amino acids of RAG1, which are required for efficient egress from nucleoli, reduces recombination activity. Our findings indicate that nucleolar sequestration of RAG1 is a negative regulatory mechanism in V(D)J recombination and identify regions of the RAG1 N-terminal region that control nucleolar association and egress.
