Open AccessInvolvement of a Short Interspersed Element in Epigenetic Transcriptional Silencing of the Amoebapore Gene in Entamoeba histolytica
Author(s) -
M. Anbar,
Rivka Bracha,
Yael Nuchamowitz,
Yan Li,
Anat Florentin,
David Mirelman
Publication year - 2005
Publication title -
eukaryotic cell
Language(s) - English
Resource type - Journals
eISSN - 1535-9778
pISSN - 1535-9786
DOI - 10.1128/ec.4.11.1775-1784.2005
Subject(s) - biology , microbiology and biotechnology , gene silencing , gene , transcription (linguistics) , chromatin immunoprecipitation , histone , promoter , gene expression , genetics , philosophy , linguistics
Transcriptional silencing of an amoebapore (ap-a ) gene occurred inEntamoeba histolytica following the transfection of plasmids containing a DNA segment (473 bp) homologous to the 5′ upstream region of the gene (R. Bracha, Y. Nuchamowitz, and D. Mirelman, Eukaryot. Cell2: 295-305, 2003). This segment contains the promoter region of theap-a gene, a T-rich stretch, followed by a truncated SINE1 (short interspersed element 1) that is transcribed from the antisense strand. Transfection of plasmids containing truncated SINE1 sequences which lack their 3′ regulatory elements upstream of theap-a gene was essential for the downstream silencing of theap-a gene while transfection with plasmids containing the entire SINE1 sequence or without the T-rich stretch promoted the overexpression of theap-a gene. Both the T-rich stretch and sequences of the 5′ SINE1 were essential for the transcription of SINE1. RNA extracts from gene-silenced cultures showed small amounts of short (∼140-nucleotide), single-stranded molecules with homology to SINE1 but no short interfering RNA. Chromatin immunoprecipitation analysis with an antibody against methylated K4 of histone H3 showed a demethylation of K4 at the domain of theap-a gene, indicating transcriptional inactivation. These results suggest the involvement of SINE1 in triggering the gene silencing and the role of histone modification in its epigenetic maintenance.