(A) Pie charts summarizing the relative abundance of LINES, SINES, LTR elements, and DNA transposons in the human genome (left) and those bound by Drosha (right). The observed and expected numbers of tags are significantly different (chi-square test, p < 10−15). See also .
(B) Chr6:21,360,000–21,368,000 region containing a HERV-H endogenous retrovirus. Gray triangles represent the two LTRs. Pink, violet, and blue boxes represent genomic fragments whose translations have similarities with Gag, Pol, and Env retroviral proteins. ChIP-seq tags density difference between Drosha siRNA and control conditions along the sequence. Positive values indicate an excess of mapped tags in the Drosha condition.
(C) Experiment was performed as in (B) except that RNAPII, RNAPII ser5, and RNAPII ser2 antibodies were used for ChIP-seq.
(D) Analysis of genes targeted by Drosha. HeLa LTR-Luc cells transfected with the indicated siRNA were analyzed by ChIP assay using antibody against Drosha (top) or by NRO (bottom). Regions amplified by q-PCR using specific oligonucleotides are indicated. ChIP results are presented as fold enrichment over that of a mock precipitation using an unrelated IgG antiserum. For NRO, values were normalized to the amount of GAPDH RNA in the same samples. The result for Scrtreated cells was attributed a value of 1. All graphs show mean ± SE from at least three independent experiments. See also .
(E) TR of RNAPII is modified by Drosha. ChIP-seq data using anti-RNAPII performed on chromatin from HeLa LTR-Luc cells transfected with the indicated siRNA were analyzed, and the TR of RNAPII was determined.
(F) A proposed model for premature termination and transcriptional repression at the HIV-1 promoter. See text for details.