A sequence motif found in aDrosophilaheterochromatin protein is conserved in animals and plants

Abstract

Modifiers of position-effect-variegation in Drosophila encode proteins that are thought to modify chromatin, rendering it heritably changed in its expressibility. In an attempt to identify similar modifier genes in other species we have utilized a known sequence homology, termed chromo box, between a suppressor of position-effect-variegation, Heterochromatin protein 1 (HP1), and a repressor of homeotic genes, Polycomb (Pc). A PCR generated probe encompassing the HP1 chromo box was used to clone full-length murine cDNAs that contain conserved chromo box motifs. Sequence comparisons, in situ hybridization experiments, and RNA Northern blot analysis suggest that the murine and human sequences presented in this report are homologues of the Drosophila HP1 gene. Chromo box sequences can also be detected in other animal species, and in plants, predicting a strongly conserved structural role for the peptide encoded by this sequence. We propose that epigenetic (yet heritable) changes in gene expressibility, characteristic of chromosomal imprinting phenomena, can largely be explained by the action of such modifier genes. The evolutionary conservation of the chromo box motif now enables the isolation and study of putative modifier genes in those animal and plant species where chromosomal imprinting has been described.

A Role for Widely Interspaced Zinc Finger (WIZ) in Retention of the G9a Methyltransferase on Chromatin

“…As expected, GLP and WIZ were identified as significantly interacting proteins (SAINT Ն 0.9). Additional known G9a-associated proteins include: chromodomain on Y-like 1 (CDYL1) (73,74), which binds methylated H3K9; histone deacetylase 1 (HDAC1) and HDAC2 (75); mesoderm induction early response 1 (MIER1) (76), which represses transcription through recruitment of HDAC1; and chromobox homologs CBX1 (or heterochromatin protein ␤ (HP1␤)) and CBX3 (HP1␥) (77)(78)(79)(80), readers of methylated H3K9. Mass spectrometry analysis by others has shown that many of these proteins interact to form complexes.…”

Clinical features of anti-chromo antibodies associated with anti-centromere antibodies

“…A highly conserved 37-amino acid region known as the 'chromo domain' was found at amino acid resides 20-56 in p25. This domain shares > 70% sequence identity with protein in Drosophila and mouse [26]. Recently it was shown that the HP1 chromo domain has chromosome binding activity and that proteins with this domain are recruited to their distinct chromosomal binding sites, probably due to protein-protein interaction [36].…”

Changes in Gene Expression Profiles in Developing B Cells of Murine Bone Marrow

“…Five of these genes code for histones, two more for chromosomal structural proteins; it is likely that the expression pattern of these genes simply reflects the cycling status of large pre-BII cells. Four genes, however, are involved in transcriptional regulation via structural changes: the modifier-1 protein is involved in heterochromatin formation (Singh et al 1991), whereas SRG-3 is associated with the SWI-SNF complex to modify locus accessibility (Jeon et al 1997). The retinoblastoma-binding proteins RbAp46 and RbAp48 are involved in histone acetylation-dependent transcriptional regulation .…”