The trithorax group and Pc group proteins are differentially involved in heterochromatin formation in Drosophila.
In Drosophila, the Polycomb group and trithorax group proteins play a critical role in controlling the expression states of homeotic gene complexes during development. The common view is that these two classes of proteins bind to the homeotic complexes and regulate transcription at the level of chromatin. In the present work, we tested the involvement of both groups in mitotic heterochromatin formation in Drosophila. Using specific antibodies, we show that some of the tested Pc-G proteins are present in heterochromatin, while all the tested trx-G proteins localize to specific regions of heterochromatin in both mitotic chromosomes and interphase nuclei. We also observed that mutations in trx-G genes are recessive enhancers of position-effect variegation and are able to repress the transcription of heterochromatic genes. These results strongly suggest that trx-G proteins, along with some Pc-G proteins, play an active role in heterochromatin formation in Drosophila.
Fanti
Laura
L
Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Genetica e Biologia molecolare, Università La Sapienza, 00185, Rome, Italy. laura.fanti@uniroma1.it
Perrini
Barbara
B
Piacentini
Lucia
L
Berloco
Maria
M
Marchetti
Enzo
E
Palumbo
Gioacchino
G
Pimpinelli
Sergio
S
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D002875:Chromosomes / Q000235:genetics; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D005801:Genes, Homeobox / Q000502:physiology; D005808:Genes, Recessive; D006570:Heterochromatin / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D006657:Histones / Q000378:metabolism; D007399:Interphase; D008938:Mitosis; D009154:Mutation / Q000235:genetics*; D063150:Polycomb Repressive Complex 1; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic