Homeotic transformations of the axial skeleton of YY1 mutant mice and genetic interaction with the Polycomb group gene Ring1/Ring1A

Segment identity in both invertebrates and vertebrates is conferred by spatially restricted distribution of homeotic gene products. In Drosophila, the expression of Homeobox genes during embryogenesis is initially induced by segmentation gene products and then maintained by Polycomb group and Trithorax group gene products. Polycomb group gene homologs are conserved in vertebrates. Murine mel-18 and closely related bmi-1 are homologous to posterior sex combs and suppressor two of zeste. Mel-18 protein mediates a transcriptional repression via direct binding to specific DNA sequences. To gain further insight into the function of Mel-18, we have inactivated the mel-18 locus by homologous recombination. Mice lacking mel-18 survive to birth and die around 4 weeks after birth after exhibiting strong growth retardation. Similar to the Drosophila posterior sex combs mutant, posterior transformations of the axial skeleton were reproducibly observed in mel-18 mutants. The homeotic transformations were correlated with ectopic expression of Homeobox cluster genes along the anteroposterior axis in the developing paraxial mesoderm. Surprisingly, mel-18-deficient phenotypes are reminiscent of bmi-1 mutants. These results indicate that the vertebrate Polycomb group genes mel-18 and bmi-1, like Drosophila Polycomb group gene products, might play a crucial role in maintaining the silent state of Homeobox gene expression during paraxial mesoderm development.

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Participation of Polycomb group gene extra sex combs in hedgehog signaling pathway

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2004.08.125 ◽

2004 ◽

Vol 323 (2) ◽

pp. 523-533 ◽

Cited By ~ 4

Author(s):

Norihisa Shindo ◽

Atsushi Sakai ◽

Kouji Yamada ◽

Toru Higashinakagawa

Keyword(s):

Signaling Pathway ◽

Hedgehog Signaling ◽

Polycomb Group ◽

Hedgehog Signaling Pathway ◽

Sex Combs ◽

Polycomb Group Gene

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Genetic interactions and dosage effects of Polycomb group genes in mice

Development ◽

10.1242/dev.125.18.3543 ◽

1998 ◽

Vol 125 (18) ◽

pp. 3543-3551 ◽

Cited By ~ 5

Author(s):

S. Bel ◽

N. Core ◽

M. Djabali ◽

K. Kieboom ◽

N. Van der Lugt ◽

...

Keyword(s):

Hox Genes ◽

Expression Patterns ◽

Axial Skeleton ◽

Polycomb Group ◽

Genetic Interactions ◽

Homeotic Gene ◽

Polycomb Group Genes ◽

Dosage Effects ◽

Somitic Mesoderm ◽

Homeotic Gene Expression

In Drosophila and mouse, Polycomb group genes are involved in the maintenance of homeotic gene expression patterns throughout development. Here we report the skeletal phenotypes of compound mutants for two Polycomb group genes bmi1 and M33. We show that mice deficient for both bmi1 and M33 present stronger homeotic transformations of the axial skeleton as compared to each single Polycomb group mutant, indicating strong dosage interactions between those two genes. These skeletal transformations are accompanied with an enhanced shift of the anterior limit of expression of several Hox genes in the somitic mesoderm. Our results demonstrate that in mice the Polycomb group genes act in synergy to control the nested expression pattern of some Hox genes in somitic mesodermal tissues during development.

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Chemokine-mediated thymopoiesis is regulated by a mammalian Polycomb group gene, mel-18

Immunology Letters ◽

10.1016/s0165-2478(01)00315-7 ◽

2002 ◽

Vol 80 (2) ◽

pp. 139-143 ◽

Cited By ~ 2

Author(s):

Kozue Miyazaki ◽

Hiroko Inoue ◽

Nobuyuki Onai ◽

Hiroto Ishihara ◽

Masamoto Kanno

Keyword(s):

Polycomb Group ◽

Polycomb Group Gene

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Polycomb Requires Chaperonin Containing TCP-1 Subunit 7 for Maintaining Gene Silencing in Drosophila

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.727972 ◽

2021 ◽

Vol 9 ◽

Author(s):

Najma Shaheen ◽

Jawad Akhtar ◽

Zain Umer ◽

Muhammad Haider Farooq Khan ◽

Mahnoor Hussain Bakhtiari ◽

...

Keyword(s):

Genetic Interaction ◽

Expression Patterns ◽

Cell Types ◽

Polycomb Group ◽

Specific Gene ◽

Cellular Memory ◽

Trithorax Group ◽

T Complex ◽

Ring Complex ◽

Active Expression

In metazoans, heritable states of cell type-specific gene expression patterns linked with specialization of various cell types constitute transcriptional cellular memory. Evolutionarily conserved Polycomb group (PcG) and trithorax group (trxG) proteins contribute to the transcriptional cellular memory by maintaining heritable patterns of repressed and active expression states, respectively. Although chromatin structure and modifications appear to play a fundamental role in maintenance of repression by PcG, the precise targeting mechanism and the specificity factors that bind PcG complexes to defined regions in chromosomes remain elusive. Here, we report a serendipitous discovery that uncovers an interplay between Polycomb (Pc) and chaperonin containing T-complex protein 1 (TCP-1) subunit 7 (CCT7) of TCP-1 ring complex (TRiC) chaperonin in Drosophila. CCT7 interacts with Pc at chromatin to maintain repressed states of homeotic and non-homeotic targets of PcG, which supports a strong genetic interaction observed between Pc and CCT7 mutants. Depletion of CCT7 results in dissociation of Pc from chromatin and redistribution of an abundant amount of Pc in cytoplasm. We propose that CCT7 is an important modulator of Pc, which helps Pc recruitment at chromatin, and compromising CCT7 can directly influence an evolutionary conserved epigenetic network that supervises the appropriate cellular identities during development and homeostasis of an organism.

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Deletion of the polycomb-group gene EZH2 causes myeloproleferative neoplasm in mice

Experimental Hematology ◽

10.1016/j.exphem.2013.05.212 ◽

2013 ◽

Vol 41 (8) ◽

pp. S54

Author(s):

Makiko Mochizuki-Kashio ◽

Goro Sashida ◽

Tomoya Muto ◽

George Wendt ◽

Atsushi Iwama

Keyword(s):

Polycomb Group ◽

Polycomb Group Gene

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E(z): a polycomb group gene or a trithorax group gene?

Development ◽

10.1242/dev.122.7.2189 ◽

1996 ◽

Vol 122 (7) ◽

pp. 2189-2197 ◽

Cited By ~ 6

Author(s):

D. LaJeunesse ◽

A. Shearn

Keyword(s):

Polycomb Group ◽

Bithorax Complex ◽

Trithorax Group ◽

Polycomb Group Genes ◽

Enhancer Of Zeste ◽

Selector Genes ◽

Homeotic Selector Genes ◽

Polycomb Group Gene ◽

Anterior Posterior ◽

Homeotic Selector

The products of the Polycomb group of genes are cooperatively involved in repressing expression of homeotic selector genes outside of their appropriate anterior/posterior boundaries. Loss of maternal and/or zygotic function of Polycomb group genes results in the ectopic expression of both Antennapedia Complex and Bithorax Complex genes. The products of the trithorax group of genes are cooperatively involved in maintaining active expression of homeotic selector genes within their appropriate anterior/posterior boundaries. Loss of maternal and/or zygotic function of trithorax group genes results in reduced expression of both Antennapedia Complex and Bithorax Complex genes. Although Enhancer of zeste has been classified as a member of the Polycomb group, in this paper we show that Enhancer of zeste can also be classified as a member of the trithorax group. The requirement for Enhancer of zeste activity as either a trithorax group or Polycomb group gene depends on the homeotic selector gene locus as well as on spatial and temporal cues.

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