Project description:We analyzed genome-wide chromatin binding of the transcription factor c-Myb using ChIP-Seq. K-562 cell lines stably expressing N-termianl 3xTY tagged Myb (pEFneo-3xTY-Myb) and control cell lines expressing the tag (pEFneo-3xTY) were used.
Project description:K562 cells, a myeloid leukemia cells line, were engineered to express a tamoxifen inducible dominant negative Myb (MERT). K562-MERT cells were cultured for 3 days in the absence and presence of 1 uM tamoxifen. The RNA was then extracted from the untreated and tamoxifen treated K562-MERT cells and submitted to Incyte Genomics for poly(A) RNA selection, probe preparation, hybridization of the labeled cDNA to the micorarray chip (Incyte Genomics) and data analysis.
Project description:MYB is a pivotal oncogenic driver in leukemia and is overexpressed through various mechanisms. Transcriptional regulation of MYB is complex with an alternative MYB promoter (TSS2) located in intron 1. Here, we identified two bidirectional enhancer RNAs transcribed from the -34 kb enhancer of MYB. These two eRNAs both upregulate MYB transcription, and promote proliferation and migration in leukemia cells. To further elucidate how eRNAs regulate MYB expression, we analyzed MYB differential exon usage in RNASeq data with the DEXSeq package after overexpression of eRNAs in K562 cells. We found that bidirectional enhancer RNAs regulate different MYB promoters. Transcription initiating from TSS2 produces N-terminally truncated MYB protein lacking the first 20 amino acids. To analyze the genes and pathways affected by both MYB isoforms, RNA-seq was performed after MYB or N-terminally truncated MYB was overexpressed in K562 cells. We found that N-terminally truncated MYB exhibits different activity in K562 cells, where it not only activates different primary targets, but also different downstream pathways altogether.
Project description:Estrogen Receptor alpha (ERα) is a key driver of most breast cancers, and it is the target of endocrine therapies used in the clinic to treat women with ERα positive (ER+) breast cancer. The two methods ChIP-seq (chromatin immunoprecipitation coupled with deep sequencing) and RIME (Rapid Immunoprecipitation of Endogenous Proteins) have greatly improved our understanding of ERα function during breast cancer progression and in response to anti-estrogens. A critical component of both ChIP-seq and RIME protocols is the antibody that is used to pull down the bait protein. To date, most of the ChIP-seq and RIME experiments for the study of ERα have been performed using the sc-543 antibody from Santa Cruz Biotechnology. However, this antibody has been discontinued, thereby severely impacting the study of ERα in normal physiology as well as diseases such as breast cancer and ovarian cancer. Here, we compare the sc-543 antibody with other commercially available antibodies, and we show that 06-935 (EMD Millipore) and ab3575 (Abcam) antibodies can successfully replace the sc-543 antibody for ChIP-seq and RIME experiments.
