メタフェーズ染色体構造:帯は,高度にATを多く含有する骨組みの差異的な折り畳み経路から生じる

Y Saitoh¹, U K Laemmli

¹Department of Biochemistry, University of Geneva, Switzerland.

Cell

|February 25, 1994

まとめ

研究者らは,染色体内の縦方向光学信号であるATキューを特定し,染色体帯状のパターンを理解するのに役立ちます. この発見は,染色体構造と組織に関する洞察を明らかにします.

科学分野:

サイトジェネティクスサイトジェネティクス
分子生物学は分子生物学である.
染色体構造について

背景:

染色体帯のパターンは,ゲノム組織と機能を理解するために不可欠です.
染色体帯の微分光の分子基礎は,長い間疑問にされてきた.
基板関連領域 (SARs) は,染色体構造に役割を果たすことが知られている.

研究の目的:

ネイティブ染色体における縦方向光学信号を特定し,特徴づけること.
AT豊富な領域,染色体帯,染色体支架の関係を解明する.
ループ・スキャフォールドモデルに基づいてネイティブ染色体の構造的組織を調査する.

主な方法:

染色体構造を視覚化するために,AT特異の色素ダウノミシンを使用した.
染色体支架を特定するために,トポイソメラーゼII (トポII) とHMG-I/Yを標的とした免疫光を用いた.
分析された光帯状のパターンは,ATが豊富な領域と支架タンパク質に関連しています.

主要な成果:

ATキュー (AT queue) と呼ばれる縦方向光学信号をネイティブ染色体で特定し,ATに富んだ支架関連領域 (SARs) と相関している.
ATキューの微分折り合いが光帯を説明することを実証しました: Q帯 (明るい信号) で緊密に折り合わされ,R帯 (鈍い信号) で展開されます.
トポイソメラーゼII (topo II) とHMG-I/Yが染色体支架の構成要素として確認され,その分布はQ型帯状パターンを反映しています.

結論:

AT豊富なSARによって形成されるATキューは,染色体帯状のパターンの重要な決定因子です.
ネイティブ染色体は,ループ・エスカフォルドモデルに従って組織され,AT列は縦軸のエスカフォルドを表しています.
この発見は,光帯の分子説明を提供し,染色体構造の理解を深める.

さらに関連する動画

07:14

Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations

Published on: September 20, 2019

07:48

Use of Time-Lapse Microscopy and Stage-Specific Nuclear Depletion of Proteins to Study Meiosis in S. cerevisiae

Published on: October 11, 2022

関連する概念動画

02:04

Polytene Chromosomes

Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...

02:30

Histone Variants at the Centromere

Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3 variants are also...

02:20

Cohesins

Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...

02:57

Attachment of Sister Chromatids

As cells progress into mitosis, the nuclear envelope breaks down, and the condensed chromosomes are exposed to the array of bipolar microtubules of the mitotic spindle. The kinetochore, a large, disc-shaped protein complex, is present at the centromere region of the sister chromatids and acts as a binding site for the microtubules. Usually, the plus-end of a single microtubule is embedded within the kinetochore. However, some kinetochores first establish lateral contact with the side-wall of a...

02:11

Forces Acting on Chromosomes

During mitosis, chromosome movements occur through the interplay of multiple piconewton level forces. In prometaphase, these forces help in chromosome assembly or congression at the equatorial plane, eventually leading to their alignment at the metaphase plate. The forces acting on the chromosomes are space and time-dependent; therefore, they vary with the position of the chromosomes as the cell progresses through mitosis.
Microtubules and motor proteins exert two types of forces on...

02:17

Separation of Sister Chromatids

At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...

関連する実験動画