A reconsideration of the mechanism of position effect.

Henikoff, Steven

doi:10.1093/genetics/138.1.1

Cited by 59 publications

(4 citation statements)

References 49 publications

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“…Interaction of chromodomain proteins with heterochromatin, therefore, is the assembly of a multicomponent complex, mediated by protein-protein interactions. Recent results suggest probably mediated through protein-protein interactions, in agreement with current models for heterochromatin a parallel between the Pdd1p-mediated deletion process reported here and V(D)J recombination during B assembly involving formation of a multicomponent complex (for review see Henikoff, 1990Henikoff, , 1994Karpen, 1994). cell maturation (Stanhope-Baker et al, 1996).…”

Section: Deletion Elements 1994) To Determine Whether Pdd1p Localizes...supporting

confidence: 90%

Pdd1p, A Novel Chromodomain-Containing Protein, Links Heterochromatin Assembly and DNA Elimination in Tetrahymena

Madireddi

Coyne

Smothers

et al. 1996

Cell

164

192

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During Tetrahymena conjugation, programmed DNA degradation occurs in two separate nuclei. Thousands of germline-specific deletion elements are removed from the genome of the developing somatic macronucleus, and the old parental macronucleus is degraded by an apoptotic mechanism. An abundant polypeptide, Pdd1p (formerly p65), localizes to both of these nuclei at the time of DNA degradation. Here we report that, in developing macronuclei, Pdd1p localizes to electron-dense, heterochromatic structures that contain germline-specific deletion elements. Pdd1p also associates with parental macronuclei during terminal stages of apoptosis. Sequencing of the PDD1 gene reveals it to be a member of the chromodomain family, suggesting a molecular link between heterochromatin assembly and programmed DNA degradation.

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Section: Deletion Elements 1994) To Determine Whether Pdd1p Localizes...supporting

confidence: 90%

Pdd1p, A Novel Chromodomain-Containing Protein, Links Heterochromatin Assembly and DNA Elimination in Tetrahymena

Madireddi

Coyne

Smothers

et al. 1996

Cell

164

192

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“…A related synapsis-dependent phenomenon has been described for dominant heterochromatic inactivation of brown (HENIKOFF 1994). The inactivation of bw+ by bd' depends on an ectopic block of centric heterochromatin on the b d chromosome being able to pair back to the centromere (HENIKOFF et al 1995;CSINK and HENIKOFF, 1996;DERNBERC et al 1996).…”

Section: Chromosome Replication and Synapsis At Bx Dpp Andmentioning

confidence: 97%

Topological Constraints on Transvection Between white Genes Within the Transposing Element TE35B in Drosophila melanogaster

Gubb¹,

Roote²,

Trenear³

et al. 1997

Genetics

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The transposable element TE35B carries two copies of the white (w) gene at 35B1.2 on the second chromosome. These w genes are suppressed in a zeste-1 (z1) mutant background in a synapsis-dependent manner. Single-copy derivatives of the original TE35B stock give red eyes when heterozygous, but zeste eyes when homozygous. TE35B derivatives carrying single, double or triple copies of w were crossed to generate flies carrying from two to five ectopic w genes. Within this range, z1-mediated suppression is insensitive to copynumber and does not distinguish between w genes that are in cis or in trans. Suppression does not require the juxtaposition of even numbers of w genes, but is extremely sensitive to chromosomal topology. When arranged in a tight cluster, in triple-copy TE derivatives, w genes are non-suppressible. Breakpoints falling within TE35B and separating two functional w genes act as partial suppressors of z1. Similarly, breakpoints immediately proximal or distal to both w genes give partial suppression. This transvection-dependent downregulation of w genes may result from mis-activation of the X-chromosome dosage compensation mechanism.

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“…This cis -inactivation might occur by the spreading of transcription-silencing factors from heterochromatin into the white gene [ 19 ]. Alternatively, the proximity to heterochromatin of white on the inverted X might expose white to a repressive environment, perhaps mediated by a cluster of heterochromatin [ 20 ].…”

Section: Position-effect Variegationmentioning

confidence: 99%