Project description:L1 retrotransposons are active elements in the genome, capable of mobilization in neuronal progenitor cells. Previously, we showed that chromatin remodeling during neuronal differentiation allows for a transient stimulation of L1 transcription. The activity of L1 retrotransposons during brain development can impact gene expression and neuronal function. Here we show that L1 neuronal retrotransposition in rodents is increased in the absence of MeCP2, a protein involved in global methylation and human neurodevelopmental diseases. Using neuronal progenitor cells derived from human induced pluripotent stem cells and human tissues, we revealed that Rett syndrome patients, with MeCP2 mutations, have increased susceptibility for L1 retrotransposition. Our data demonstrate that disease-related genetic mutations can influence the frequency of neuronal L1 retrotransposition, thereby increasing brain-specific genetic mosaicism. Genetic reprogramming of somatic cells to a pluripotent state (induced pluripotent stem cells, or iPSCs) by over-expression of specific genes has been accomplished for fibroblasts derived from controls and Rett syndrome patients. Different clones from each were compared to respective original fibroblasts and a human embryonic stem cell line. Gene expression profiles measured using human genome Affymetrix Gene Chip arrays were grouped by hierarchical clustering, and correlation coefficients were computed for all pair-wise comparisons.

2010-11-11 | E-GEOD-21037 | biostudies-arrayexpress

Homo sapiens

Project description:Single-neuron whole-genome analysis of somatic mutation of aging and early-onset neurogeneration in the human brain

| PRJNA395346 | ENA

Homo sapiens

Project description:Widespread somatic L1 retrotransposition occurs early during gastrointestinal cancer evolution

| PRJNA268381 | ENA

Widespread somatic L1 retrotransposition occurs early during gastrointestinal cancer evolution

Project description:Somatic L1 retrotransposition events have been shown to occur in epithelial cancers1-8. Here, we attempted to determine how early somatic L1 insertions occurred during the development of gastrointestinal (GI) cancers. Using L1-targeted resequencing (L1-seq), we studied different stages of four colorectal cancers arising from colonic polyps, seven pancreatic carcinomas, as well as seven gastric cancers. Surprisingly, we found somatic L1 insertions not only in all cancer types and metastases, but also in colonic adenomas, well-known cancer precursors. Some insertions were also present in low quantities in normal GI tissues, occasionally caught in the act of being clonally fixed in the adjacent tumors. Insertions in adenomas and cancers numbered in the hundreds and many were present in multiple tumor sections implying clonal distribution. Our results demonstrate that extensive somatic insertional mutagenesis occurs very early during the development of GI tumors, probably before dysplastic growth. Here we show Human SNP 6.0 Array experiments on DNAs from four colorectal cancer patients (1BV, 2BV, 3BV, and 4BV) with polyps and metastases. Here we characterize the samples for CNVs and compare the samples' CNV status to their respective somatic L1 retrotransposition profile.

2015-08-10 | E-GEOD-63601 | biostudies-arrayexpress

L1 retrotransposition in neurons is mediated by MeCP2

2010-11-11 | GSE21037 | GEO

Somatic L1 Retrotransposition of Colorectal Tumors

Project description:Somatic L1 Retrotransposition of Colorectal Tumors

| PRJNA173389 | ENA

Homo sapiens

Project description:Somatic mutation load in clones of single human cells

| PRJNA336369 | ENA