Name: how plant cells build a new wall
Uploaded: 2021-04-07T12:12:02.000Z
Duration: 1 min 59 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Life Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-4

The Phragmoplast

植物の細胞は硬い細胞壁に囲まれているため、細胞が外部から収縮して分裂しにくくなっています。したがって、植物細胞は、2つの娘核の間に新しい細胞壁を「裏返し」に形成することにより分裂します。フラグモプラストと呼ばれる植物の特殊な構造が、新しい細胞壁の形成を導きます。
細胞分裂面は、将来の細胞壁形成部位であり、細胞周期のG1期に形成される微小管とアクチンフィラメントからなる前期バンドによって特徴づけられます。前期バンドは細胞皮質で集まり、M期の開始時に消失します。
有糸分裂中、染色体は分離し、反対の極に移動し始めます。極では、分離した染色体の周りに核膜が形成され、紡錘体が消え始めます。有糸分裂紡錘体の残りの微小管は、フラグモプラストを形成します。
フラグモプラスト微小管は極性で、赤道面の近くにプラス端があり、極の近くにマイナス端があります。
ゴルジ体は小さな小胞を分泌し、モータータンパク質によって微小管に沿って細胞中心に運ばれます。これらの小胞には、新しい細胞壁の合成に必要な2つの重要な成分である多糖類と糖タンパク質が充填されています。小胞の融合により、初期細胞プレートと呼ばれる円盤状の構造が形成されます。
フラグモプラスト微小管は、細胞プレートの自由縁で正常に再生され、フラグモプラストがプレートを横方向に伸ばすことができます。新しい細胞プレートは、M期の前に前期バンドによってマークされた部位で母細胞壁と結合します。原形質膜が細胞プレートと融合し、新しい細胞壁が形成され、2つの娘細胞が分離されます。

<ol>
	<li>細胞の分子生物学、アルバーツ、第6版。997-999ページ。</li>
	<li>「植物の細胞骨格」 植物科学の批判的レビュー 8, no. 2 (1989): 131-167.</li>
	<li>「植物細胞における微小管組織と微小管関連タンパク質」 in International review of cell and molecular biology, vol. 312, pp. 1-52.アカデミックプレス、2014年。</li>
	<li>Fosket、DE「発達に重要な植物細胞の特性」 植物の成長と発達。分子的アプローチ。アカデミックプレスサンディエゴ、1994年。</li>
	<li>Casem、Merri Lynn、ed. 細胞生物学のケーススタディ。アカデミックプレス、2016年。</li>
</ol>

隔膜プラスト

細胞分裂は生物の成長と発達に不可欠です。動物細胞では、中央紡錘体とそれに関連するタンパク質が中央体を形成し、この構造は細胞質分裂に重要な役割を果たします。植物では、中央紡錘体が微小管、アクチン、その他の細胞成分とともに細胞質分裂に必要な隔膜形成体に成熟します。静止した中央体とは異なり、隔膜形成体は遠心力によって膨張し、最終的に新しい細胞壁の形成につながります。

成熟した隔膜プラストはドーナツ型で、外側の先行領域、中間の移行ゾーン、および内側の遅行領域を含んでいます。先頭領域では、新しい微小管が連続的に組み立てられます。微小管の核形成は、GCP1～GCP6の6つのサブユニットを含むγ-チューブリン環複合体(γ-TuRC)によって開始されます。しかし、γ-TuRCは微小管と直接相互作用することができません。したがって、微小管相互作用タンパク質複合体であるオーグミンは、微小管へのγ-TuRCの動員を媒介します。隔膜形成体に存在する微小管は、近くのゴルジ体によって生成される分泌小胞を輸送するためのトラックとして機能します。

中間の移行ゾーンでは、小胞は最初に細管様構造に移行し、その後相互接続して絡み合った管状ネットワークを形成します。分泌小胞を継続的に追加すると、親細胞膜と接触するまで管状ネットワークが外側に向かって成長します。小胞膜は娘細胞の細胞膜を形成するために使用され、小胞内に存在する生体分子は2つの娘細胞の膜の間に存在する細胞板を構築するために使用されます。

遅行領域では、微小管が解重合し、細胞プレートの成熟部分が残ります。完全に形成された細胞板は、その後、2つの娘細胞を分離する細胞壁に発達します。先端での微小管の重合と後続領域での微小管の解重合により、隔膜プラストと細胞板が親細胞壁と結合するまで外側に拡張します。隔膜形成体機能の不全は、多核細胞および胎児致死表現型を引き起こす可能性があります。

細胞分裂は、生物の成長と発達に不可欠です。動物細胞では、中央紡錘体とそれに関連するタンパク質が中体を形成します...

Education

JoVE Core

Molecular Biology

分子生物学

Unit 2

ユニット2

Cell Division

細胞分裂

KEY TERMS AND CONCEPTS

主要用語と概念

how plant cells build a new wall

Plant cells build a new wall during cytokinesis with help from the phragmoplast. This plant structure forms from the central spindle and related cell parts as the cell finishes dividing. In animal cells, the comparable structure is the midbody, but in plants the phragmoplast expands outward to guide new wall formation.

The mature phragmoplast has a donut-like shape. It has an outer leading region, a middle transition zone, and an inner lagging region. New microtubules are assembled continuously in the leading region. Microtubule nucleation begins with the gamma-tubulin ring complex, or gamma-TuRC, which contains six subunits called GCP1 through GCP6. Because gamma-TuRC cannot attach to microtubules on its own, augmin, a microtubule-interacting protein complex, helps recruit it to the microtubules.

The microtubules in the phragmoplast act as tracks for secretory vesicles from the nearby Golgi body. In the middle transition zone, these vesicles first change into tubule-like structures. They then connect to form an intertwined tubular network. As more vesicles are added, the network grows outward until it reaches the parental cell membrane.

The vesicle membranes become the plasma membrane of the daughter cells. The materials inside the vesicles help build the cell plate between the two daughter-cell membranes. In the lagging region, the microtubules break down, leaving the mature part of the cell plate behind. The finished cell plate then develops into the cell wall that separates the two daughter cells.

This outward growth depends on microtubules being built at the leading end and broken down at the lagging end. If phragmoplast function fails, cells can become multinucleated. It can also lead to embryonic lethal phenotypes.

How Plant Cells Build a New Wall

mitosis and cytokinesis

Mitosis and Cytokinesis Stages

Mitosis and cytokinesis are the two main steps of cell division. Mitosis is the process that divides the nucleus, while cytokinesis splits the rest of the cell. During mitosis, the cell’s genetic material is separated into two sets. This helps form two new nuclei with the same genetic information. Cytokinesis then completes division by separating the cytoplasm, which creates two daughter cells. These stages work together to make cell division possible in growing and repairing tissues.

duplication of chromatin structure

Chromatin Rebuilding During DNA Replication

Chromatin rebuilding during DNA replication helps cells copy DNA and pass on chromosome structure to daughter cells. During cell division, the genome must be disrupted and then reassembled across the whole chromosome. This process allows chromatin to be inherited, rebuilt, and maintained in new cells. The basic unit of chromatin is the nucleosome. A nucleosome contains DNA wrapped around an octamer of histone proteins, with short linker DNA between neighboring nucleosomes. The histone proteins...

cohesins

Cohesins in Meiosis and Genetic Disorders

Cohesin protein complexes act like molecular glue that keeps sister chromatids together. They are important in both mitosis and meiosis. In mitosis, cohesin complexes are removed from chromosomes before anaphase begins. Meiosis has two rounds of chromosome separation. Meiosis I separates homologous chromosomes, while Meiosis II separates sister chromatids. This process produces four daughter cells. The Meiosis I cohesin complex is made of four subunits: Smc1, Smc3, Rec8, and Scc3. Rec8...

condensins

How Condensins Shape Mitotic Chromosomes

Condensins shape chromosomes during mitosis, the stage when a cell divides. These large protein complexes use ATP, the cell’s energy molecule, to help turn loose post-interphase DNA into compact, separate chromosomes. They organize and segregate chromosomal DNA so it can be passed on correctly. Plant and animal cells contain two condensin complexes: condensin I and condensin II. Each complex has five subunits. Two are SMC, or Structural Maintenance of Chromosomes, subunits. One is a kleisin...

the mitotic spindle

How the Mitotic Spindle Separates Chromosomes

The mitotic spindle is a microtubule-based structure that helps separate chromosomes during cell division. It forms in eukaryotic cells and moves sister chromatids to opposite ends of the parent cell. This leaves each new cell nucleus with the correct genetic material. A bipolar spindle has two poles, and that shape is important for chromosome segregation. In many animal cells, two centrosomes are present when mitosis begins. Each centrosome helps organize a circular set of microtubules at one...

centrosome duplication

Centrosome Duplication in the Cell Cycle

Centrosome duplication is a key part of the animal cell cycle. The centrosome is the main microtubule organizing center, or MTOC, in animal cells. It contains two cylindrical centrioles at its core. Each centriole has nine sets of three microtubules held together by proteins. The two centrioles sit at right angles and are surrounded by the pericentriolar matrix, or PCM, a shapeless protein cloud. Duplication starts early in the cell cycle so each daughter cell can receive a centrosome after...

microtubule instability

Microtubule Growth and Shrinkage

Microtubules are hollow, cylindrical filaments in the cell. They are about 25 nm wide and can range from 200 nm to 25 μm in length. Their main building blocks are GTP-bound tubulin subunits that form αβ-heterodimers, which then assemble into protofilaments. These protofilaments join by lateral bonds to create stable microtubule cylinders. Microtubules are highly dynamic because they repeatedly assemble and break down. They can even grow on one end while shrinking on the other at the same time.

spindle assembly

How the Mitotic Spindle Forms

The mitotic spindle forms through centrosome-mediated, chromatin-mediated, and microtubule-mediated pathways. These pathways often work at the same time. Together, they build a strong spindle apparatus for cell division. In most cells, centrosomes are the main sites where microtubules begin to grow. During the G2 to prophase transition, centrosomes mature and make more microtubules. The growing microtubules extend from both centrosomes, and their plus-ends search for chromosomes by attaching...

attachment of sister chromatids

Kinetochore-Microtubule Binding in Mitosis

Kinetochore-microtubule binding helps chromosomes line up and separate during mitosis. After the nuclear envelope breaks down, condensed chromosomes are exposed to the bipolar microtubules of the mitotic spindle. The kinetochore is a large, disc-shaped protein complex at the centromere region of each sister chromatid, and it serves as the microtubule binding site. Usually, the plus-end of a single microtubule inserts into the kinetochore. In some cases, a kinetochore first makes lateral...

forces acting on chromosomes

Chromosome Movement During Mitosis

Chromosome movement during mitosis depends on several small forces that act at different times and positions in the cell. In prometaphase, these forces help chromosomes move to the equatorial plane and line up at the metaphase plate. Because the forces change with location and stage, chromosome behavior also changes as mitosis continues. Microtubules and motor proteins create two main kinds of force on chromosomes: poleward force and anti-poleward force, also called polar-ejection force.

separation of sister chromatids

Anaphase Start and Chromatid Release

Anaphase starts when sister chromatids are released from one another and pulled toward opposite spindle poles. Before that happens, cohesion along the chromosomal arms is reduced from prophase to metaphase, which helps the sister chromatids resolve. A residual cohesin link still holds them together until the metaphase-to-anaphase transition. This leftover connection helps prevent early separation and reduces the risk of aneuploidy, or the wrong number of chromosomes, in daughter cells. At the...

the spindle assembly checkpoint

How Cells Safeguard Chromosome Separation

The spindle assembly checkpoint helps cells safeguard chromosome separation during anaphase. It acts as a molecular surveillance system. The checkpoint checks whether the steps needed for chromosome segregation are complete before the cell moves on. Many proteins work together to control this checkpoint. If mutations affect these proteins, a cell may enter anaphase too early. Chromosomes can then separate before the needed steps are finished. When this happens, the daughter cells may receive...

anaphase a and b

Chromatid Movement by Microtubule Forces

Chromatid movement during anaphase depends on microtubule forces at the spindle. Kinetochore microtubules grow from the spindle poles, and their plus ends attach to kinetochores on sister chromatids. The kinetochore protein complex Ndc80 makes low-affinity links with the microtubule plus end.

the contractile ring

How Cells Build the Contractile Ring

Contractile rings are built from microfilaments and help separate daughter cells during cytokinesis. This ring forms as the cell cycle moves forward, but the exact timing and coordination with other cell cycle events are still not fully understood. RhoA, a small GTPase in the Ras superfamily, controls contractile ring assembly and function. The inactive form of RhoA is bound to GDP. A guanine nucleotide exchange factor, or Rho-GEF, is located in the cortex region, where the next cell division...

determining the plane of cell division

How Cells Set the Division Plane

How cells set the division plane during cell division affects daughter cell size and, in many cases, cell fate. The plane of division is perpendicular to the plane of chromosome segregation. Different organisms use different cues to place it, based on their shape and needs. In animal cells, the cleavage furrow forms along the division plane from the cell cortex, the area just below the plasma membrane. The mitotic spindle is the main guide for this position. If the spindle axis changes, the...

the phragmoplast

Plant cells build a new wall during cytokinesis with help from the phragmoplast. This plant structure forms from the central spindle and related cell parts as the cell finishes dividing. In animal cells, the comparable structure is the midbody, but in plants the phragmoplast expands outward to guide new wall formation. The mature phragmoplast has a donut-like shape. It has an outer leading region, a middle transition zone, and an inner lagging region. New microtubules are assembled...

distribution of cytoplasmic content

How Organelles Are Split During Cytokinesis

Cytokinesis splits a cell’s chromosomes and organelles into two daughter cells. Before cell division, organelles grow and divide. They cannot be made from scratch, so each daughter cell must inherit at least one copy to survive. Many details of this organelle sorting process are still not fully known. The cytoplasm contains organelles, salts, proteins, and water. Small organelles such as peroxisomes and lysosomes can be shared by simple diffusion. Because cells contain many copies of these...

anaphase promoting complex

APC Activates Chromosome Separation

The anaphase-promoting complex, or APC, helps control cell cycle progression by destroying specific proteins at the right time. These proteins are tagged with ubiquitin by ubiquitin ligases and then broken down by the proteasome. The SCF (Skp1/Cullin/F-box) complex and APC are two major ubiquitin ligases involved in this process. SCF stays active throughout the cell cycle, but APC turns on during the metaphase-to-anaphase transition. APC becomes active when Cdc20 or Cdh1 binds to it. These...

key terms and concepts

Learn how the phragmoplast helps plant cells complete cytokinesis, guide vesicles, and form the new cell plate and cell wall.

How Plant Cells Build a New Wall | JoVE K12

molecular biology

JoVE Core 分子生物学は、明確で簡潔なアニメーション ビデオ レッスンを通じて細胞の分子プロセスを紹介します。さらに、科学者の実際のビデオでは、これらの概念の応用が現代の研究室での実際の実験を通じて実証されています。

new-york-state-science-learning-standards

New York State Science Learning Standards

Inheritance and Variation of Traits

HS-LS1-4.

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10647.jpg

Cell Structure

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

Visualizing Onion and Cheek Cells
ExpandImmediately before the experiment, wash and peel onion bulbs for the class.
Remove the entire brown outer skin and ...

Visualizing Onion and Human Cells
ExpandIn this experiment you will prepare different types of cells from a plant and animal, onion and human ...

What are Cells?

Cell Diversity

The concept of a cell started with microscopic observations of dead cork tissue by Robert Hooke in 1665. Hooke coined the term &#34;cell&#34; based on the ...

Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

The Central Dogma

The DNA Helix

Nucleic Acids

DNA as a Genetic Template

Structure of a Gene

A gene is the fundamental unit of heredity. Every individual has two copies of each gene, one inherited from each parent. Although most people contain the ...

Chromosome Structure

Base-pairing and DNA Repair

What is Gene Expression?

A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised&#160; of nucleotides and proteins are ...

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form ...

Protein Families

Types of RNA

Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse ...

Conservation of Protein Domains

Transcription

Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. ...

Globular and Fibrous Proteins

Translation

Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes ...

Intrinsically Disordered Proteins

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Protein Complex Assembly

Protein and Protein Structures

Conjugated Proteins

Proteins: From Genes to Degradation

Amyloid Fibrils

What are Proteins?

Proteins are polymers of amino acids linked together by peptide bonds. Proteins and polypeptides are interchangeably used to refer to long chains of amino ...

Ligand Binding Sites

Protein Organization

Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular ...

Protein-Protein Interfaces

Protein Folding

Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to ...

Conserved Binding Sites

Cofactors and Coenzymes

Enzymes are proteins made of amino acids. The functional group of each constituent amino acid catalyzes a wide variety of chemical reactions via ionic ...

Cooperative Allosteric Transitions

Protein Kinases and Phosphatases

GTPases and their Regulation

Covalently Linked Protein Regulators

protein-complexes-with-interchangeable-parts

Protein Complexes with Interchangeable Parts

Mechanical Protein Function

Structural Protein Function

Protein Networks

Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells. [Assessment Boundary: Assessment does not include identification of specific cell or tissue types, whole body systems, specific protein structures and functions, or the biochemistry of protein synthesis.]

HS-LS1-1

Levels of Organization

Biological organization is the classification of biological structures, ranging from atoms at the bottom of the hierarchy to the Earth&#x27;s biosphere. ...

Animal and Plant Cell Structure

Animal and plant cells not only differ in their structure, function, and mode of nutrition but also in how they reproduce, specialize, and organize into ...

structural-organization-of-the-human-body-an-overview

Structural Organization of the Human Body: An Overview

It is convenient to consider the body&#39;s structures in terms of fundamental levels of organization that increase in complexity: subatomic particles, ...

Overview of Human Digestion

The human body contains a monogastric digestive system. In a monogastric digestive system, the stomach only contains one chamber in which it digests food. ...

Anatomy of the Intestines

Although digestion of proteins, carbohydrates, and lipids may begin in the stomach, it is completed in the intestine. The absorption of nutrients, water, ...

Accessory Organs

Accessory organs are those that participate in the digestion of food but do not come into direct contact with it like the mouth, stomach, or intestine do. ...

Lipid Digestion

Lipids are large molecules that are generally not water-soluble. Since most of the digestive enzymes in the human body are water-based, there are specific ...

Protein Digestion

Protein digestion begins in the stomach, where the highly acidic environment can easily disrupt protein structure by exposing the peptide bonds of ...

Carbohydrate Digestion

Carbohydrate digestion and metabolism break down simple and complex carbohydrates from food into saccharides (i.e., sugars) for the body to use as energy. ...

What is a Nervous System?

Overview

The nervous system is the collection of specialized cells responsible for maintaining an organism&rsquo;s internal environment and coordinating ...

The Parasympathetic Nervous System

Overview

The parasympathetic nervous system is one of the two major divisions of the autonomic nervous system. This parasympathetic system is responsible ...

The Sympathetic Nervous System

Overview

The sympathetic nervous system&mdash;one of the two major divisions of the autonomic nervous system&mdash;is activated in times of stress. It ...

Oogenesis

In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from ...

What is a Sensory System?

Sensory systems detect stimuli&mdash;such as light and sound waves&mdash;and transduce them into neural signals that can be interpreted by the nervous ...

Fertilization

During fertilization, an egg and sperm cell fuse to create a new diploid structure. In humans, the process occurs once the egg has been released from the ...

What is the Skeletal System?

Overview

The adult human skeleton comprises 206 bones that are connected through cartilage, tendons, and ligaments. The skeleton provides a rigid ...

an-introduction-to-the-zebrafish-danio-rerio

An Introduction to the Zebrafish: Danio rerio

Zebrafish (Danio rerio) are small freshwater fish that are used as model organisms for biomedical research. The many strengths of these fish include their ...

Physiology of the Circulatory System

Homeostasis
Conditions in the external environment of an organism can change rapidly and drastically. To survive, organisms must maintain a fairly ...

Anatomy of the Circulatory System

The human circulatory system consists of blood, blood vessels that carry blood away from the heart, around the body, and back to the heart, and the heart ...

Measuring Blood Pressure
ExpandTo prepare for the blood pressure exercise, simply place the appropriate number of alcohol swabs, sphygmomanometers, and ...

Anatomy of the Heart

The human heart is made up of three layers of tissue that are surrounded by the pericardium, a membrane that protects and confines the heart. The ...

Measuring Circulatory System Function in Humans
ExpandBefore starting the experiment go to the front of the room and collect an alcohol swab, a ...

Blood Flow

Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The ...

What Are Osmoregulation and Excretion?

Organisms must keep bodily fluids at a constant temperature and pH while maintaining specific solute concentrations in order to support life functions. ...

Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. [Clarification Statement: Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, and organism movement in response to neural stimuli. An example of an interacting system could be an artery depending on the proper function of elastic tissue and smooth muscle to regulate and deliver the proper amount of blood within the circulatory system.] [Assessment Boundary: Assessment does not include interactions and functions at the molecular or chemical reaction level.]

HS-LS1-2

How Plant Cells Build a New Wall

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