Premium
Transcriptional silencing by the Polycomb protein in Drosophila embryos.
Author(s) -
Müller J.
Publication year - 1995
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1995.tb07104.x
Subject(s) - biology , gene silencing , polycomb group proteins , drosophila (subgenus) , drosophila melanogaster , microbiology and biotechnology , genetics , embryo , rna interference , rna , repressor , gene , transcription factor
Polycomb group (Pc‐G) proteins act to keep homeotic genes stably and heritably silenced during Drosophila development. Here, it is shown that Polycomb (Pc), one of the Pc‐G proteins, acts as a transcriptional silencer in Drosophila embryos if tethered to reporter genes by the DNA binding domain of GAL4 (i.e. as a GAL‐Pc fusion protein). The results suggest that silencing by GAL‐Pc requires the C‐terminal portion of Pc, but not the chromodomain. If a pulse of Gal‐Pc is provided, synthetic reporter genes are repressed, though only transiently. In contrast, reporter genes containing homeotic gene sequences remain stably and heritably silenced in a Pc‐G gene‐dependent fashion, even when GAL‐Pc is no longer present. This implies that GAL‐Pc recruits Pc‐G proteins to DNA and suggests that maintenance of silencing requires the anchoring of Pc‐G proteins to specific cis‐regulatory sequences present in homeotic genes. The extent of DNA over which the Pc‐G machinery acts is quite selective, as silencing established on one enhancer does not necessarily ‘spread’ to a juxtaposed synthetic enhancer.