Cell Nucleus
From CellBiology
Introduction
This lecture introduces the nucleus and how information is transferred
from stable stored information (DNA) converted to an intermediate
(mRNA, rRNA, tRNA) of variable stability, exported from the nucleus to
the cytoplasm where mRNA is then translated into Protein. This is gene
expression, the products of this process are used either within the cell,
exported (exocytosis) or used to replace worn out components.
We will study this topic looking at the key organelle in this process, the
nucleus.
Nucleolar Assembly​ Movie | Movie - nuclear pore complexes
(http://jcb.rupress.org/cgi/content/full/154/6/1147/FIG6/DC1)
Eukaryotic Cell Physical Compartments
Lecture Archive: 2016 (https://cellbiology.med.unsw.edu.au/cellbiology/index.php?title=Cell_Nucleus&oldid=58799) | 2016 PDF | 2015
(https://cellbiology.med.unsw.edu.au/cellbiology/index.php?title=Cell_Nucleus&oldid=51902) | 2014
(http://php.med.unsw.edu.au/cellbiology/index.php?title=Cell_Nucleus&oldid=48075) | 2013
(http://php.med.unsw.edu.au/cellbiology/index.php?title=Cell_Nucleus&oldid=42432) | 2010 | 2009 | 2008 Online content
(http://cellbiology.med.unsw.edu.au/units/science/lecture0804.htm)
MH - note that content listed below will not match exactly current lecture structure but has been selected as having similar content.
Objectives
Understand the concept of the cell nucleus
Understand the overall structure and components within the nucleus
Understand the functions of the nucleus
Brief understanding of chromosomal structure
Eukaryotes
Difference between Prokaryotes and Eukaryotes
Cytoskeleton
DNA structure
circular, linear
Packing (histones)
RNA processing (splicing)
Eukaryote Gene Expression
DNA -> mRNA -> Protein
DNA (transcription) -> mRNA (translation) -> Protein (function)
​Translation
Page | Play
Nucleus
DNA (transcription) -> mRNA Nuclear processing (export)
DNA -> mRNA splicing (introns removed, exons joined) -> mRNA
Cytoplasm
mRNA (translation by ribosomes) -> Protein (processing)
Protein Processing cytoplasm (free ribosomes), rough endoplasmic reticulum
(bound ribosomes)
rough endoplasmic reticulum (tem)
Some proteins are returned to the nucleus by a Nuclear Localization Sequence (NLS)
SV40 Large T-antigen (http://www.plosone.org/article/fetchObject.action?
uri=info:doi/10.1371/journal.pone.0010475.g001&representation=PNG_M) - PKKKRKV (single part)
nucleoplasmin - KR[PAATKKAGQA]KKKK (two part) two clusters of basic amino acids separated by 10 amino acids.
Membrane Evolution
Postulated that an early "coating" structure lead to the infolding of the primitive plasma
membrane to form the many membrane covered organelles in the cytoplasm.
These modules may also be the evolutionary precursor to the nuclear pore structures and
account for the double membrane that coats the nucleus.
Nuclear Compartment
Nuclear envelope
Nuclear cytoskeleton
Nucleolus
Chromosome territories
Euchromatin is a lightly packed form of chromatin (DNA, RNA and protein)
Heterochromatin is a tightly packed form of DNA
Interchromatin compartment
“speckles” interchromatin granule clusters
Splicing speckles or SC 35 domains
thought to be sites of storage of mRNA splicing factors
nuclear bodies - Cajal and PML
Nucleus Membrane Evolution
Links: MBOC - A cross-sectional view of a typical cell nucleus
(http://www.ncbi.nlm.nih.gov/books/NBK26821/?rendertype=figure&id=A606)
Nucleus Size
cell "karyoplasmic ratio" relatively constant (ratio of nuclear volume to cell volume)
most other cellular organelles (ER and mitochondria) can vary greatly in
amounts
multinucleated fission yeast cells
relative amount of cytoplasm surrounding each nucleus controls the size of
individual nuclei
Links: Nuclear size control in fission yeast. Neumann FR, Nurse P. J Cell Biol. 2007 Nov
19;179(4):593-600. PMID: 17998401 (http://www.ncbi.nlm.nih.gov/pubmed/17998401)
Nuclear envelope and endoplasmic reticulum system
Nuclear Envelope
Forms structural compartment
Nuclear envelope two concentric membranes
Breaks down each mitosis (recycled)
Outer membrane continuous with Endoplasmic Reticulum (Endoplasmic Reticulum is covered in Lecture 5)
Contains holes “nuclear pores”
The Cell - Figure 8.1. The nuclear envelope (http://www.ncbi.nlm.nih.gov/books/bv.fcgi?
highlight=nuclear%20envelope&rid=cooper.figgrp.1325)
Nuclear Cytoskeleton
Nuclear architecture
The nuclear cytoskeleton has 2 layers
outer - less organised surrounds nuclear envelope
inner - nuclear lamina - thin shell (20 nm) underlying the nuclear envelope
associates with both the inner nuclear membrane and underlying chromatin
can regulate gene expression
provides anchor sites for nuclear pore complexes
broken down each cell division
Neural Development - Movie - Nucleus position within the cell is a signal for neural fate
(https://embryology.med.unsw.edu.au/embryology/index.php/Interkinetic_Nuclear_Migration_Movie).
Cytoplasmic
cytoskeleton migrating
neuron
Nuclear pores (red)
cytoskeleton (green)
chromatin (blue)
Nuclear Lamin A
Lamin B1 in mitosis
Nuclear lamins and
splicing factors
Muscle satellite cell
lamin A/C expression
heterochromatin (green)
LaminA/C (red)[1]
Links: MBOC - A cross-sectional view of a typical cell nucleus (http://www.ncbi.nlm.nih.gov/books/NBK26821/?
rendertype=figure&id=A606)
Nuclear Lamins
Intermediate filaments covered in Cytoskeleton Lecture – Intermediate Filaments
Lamins - Class V intermediate filaments
Vertebrate lamins are classified into 2 types - A and B
10 nm in diameter, forms rope-like networks
polypeptide form dimers - central alpha-helical regions of two polypeptide chains
are wound around each other
assembly - head-to-tail association of dimers form linear polymers, side-by-side
association of polymers form filaments
B-type - B1 and B2 (586 aa protein, Mr 66,334 Da) lamins are ubiquitously
expressed throughout development
A-type - lamins A and C (Mr 74 kD and 65 kD) lamins in many organisms
expression does not appear until midway through embryogenesis (possible role in
differentiation)
lamins phosphorylation state affects nuclear envelope assembly state
(dephosphorylation nuclear envelope assembly, phosphorylation nuclear envelope
disassembly)
Lamins also link DNA to nuclear envelope (Lamin B1 interacts with chromatin)
​Lamin A
Page | Play
Nuclear lamina and lamina-interacting
proteins
Nucleoskeleton to the cytoskeleton
complexes
Nuclear Envelope showing underlying nuclear
matrix (green) (EM Image Martin Goldberg)
Lamin Abnormalities - (laminopathies) mutations in lamins can lead to human disease (Hutchinson-Gilford Progeria Syndrome)
Links: MBOC - A cross-sectional view of a typical cell nucleus (http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=mboc4.figgrp.606) |
Nature Medicine - Image - The nuclear membranes include the interconnected but distinct inner and outer nuclear membranes and the nuclear
pore membrane (http://www.nature.com/nm/journal/v6/n2/fig_tab/nm0200_136_F1.html) MBOC - The breakdown and re-formation of the
nuclear envelope during mitosis (http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=mboc4.figgrp.2174) | The Cell - Intermediate Filament
Proteins (http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=cooper.table.1810) | The Cell - Model of lamin assembly
(http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=cooper.figgrp.1328) | Abcam - Lamin B1 antibody - Nuclear Envelope Marker
(http://www.abcam.com/index.html?datasheet=16048#ab16048-IF-Im1.jpg) | OMIM - Lamin A/C
(http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=150330) | OMIM - Lamin B1 (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?
id=150340) |
Nuclear Transport History
1999 Nobel Prize Medicine - Günter Blobel for the discovery that "proteins have intrinsic signals that govern their transport and localization
in the cell"
Links: 1999 Nobel Prize Medicine - Günter Blobel (http://nobelprize.org/nobel_prizes/medicine/laureates/1999/press.html)
Nuclear Pores
Protein complex
External diameter of about 120 nm (30 times the size of a ribosome)
Channel diameter 25 nm
channels between nucleus and cytoplasm (import/export)
passive passage of small polar molecules, ions, (<40-60 kDa)
active (selective/ regulated) passage of larger macromolecules, proteins and RNAs
importin - cytosolic protein
Nuclear pore EM structure timeline[2]
Movie - NPC movement in interphase
Nuclear pore complex
Links: JCB Movie - Nuclear Pore Complex movement in interphase
(http://jcb.rupress.org/content/suppl/2001/07/11/200101089.F4.DC1)
Nuclear Bodies
Functional compartments
Nucleus Movie 1
Cajal Bodies
also called - nucleolar accessory bodies, coiled body, gems
0.1 - 2.0 microns, 1-10/ nucleus
Gems and Cajal bodies two forms of same structure
GEMS (Gemini of coiled bodies)
proposed sites where small nuclear ribonucleoproteins (snRNPs) and small nucleolar RNAs (snoRNPs) are modified.
snRNPs are particles that combine with pre-mRNA and various proteins to form spliceosomes
snoRNAs are a class of small RNA molecules that are involved with modifications of ribosomal RNAs (rRNAs) and other RNA
genes
Cajal bodies were first reported in 1903 by the Spanish cytologist/histologist Ramón y Cajal, who christened them "nucleolar accessory
bodies".
Cajal, S.R. 1903. Un sencillo método de coloración selectiva del retículo protoplásmico y sus efectos en los diversos órganos nerviosos de
vertebrados e invertebrados. Tra. Lab. Invest. Biol. 2:129–221.
See also Nature Reviews - The centennial of the Cajal body
PML Bodies
promyelocytic leukaemia nuclear bodies
also called PODs, ND10 or Kremer bodies
Function unknown
regulation of diverse cellular functions?
viral infection, cellular transformation, innate immunity, growth control, apoptosis
dynamic hubs sensing stress and DNA damage
Chromosomes
not “visible” at interphase, condense for mitosis (1,000 fold)
condensation allows chromosomes to move along mitotic spindle without breaking or tangling
eukaryotes have separate chromosomes
Human 23 pairs, 22 autosome pairs, 2 sex chromosomes
diploid 2 copies of each chromosome (inherited one male/one female)
except male sex chromosomes X from mother Y from father
DNA and protein
packing of DNA
DNA structure
encodes genome (humans 30,000 genes, draft sequence published in 2001)
DNA genes encode RNA and proteins
DNA can also encodes nothing
Chromosome Territories
Space within the nucleus occupied by individual chromosomes
Several different models as to how these territories interact
Intrachromosomal domains possibly RNA processing and transport
Links: MBOC - Selective painting of two interphase chromosomes in a human peripheral lymphocyte
(http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=mboc4.figgrp.686) | The Cell - Chromosome Territories
(http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=cooper.figgrp.1352)
Nucleolus
Appearance
Fibrillar center, dense fibrillar component, and granular component
Nucleolus changes during the cell cycle:
during mitosis - nucleolus breaks up as chromosomes condense
after mitosis - nucleolus reforms from coalesce of tips of 10 chromosomes
Function
Sites of ribosomal (rRNA) gene transcription, processing, and ribosome assembly
Nucleolus size depends on cell metabolic activity
Sites of ribosomal (rRNA) gene transcription, processing, and ribosome assembly
All cells contain multiple copies of rRNA genes
Links: Movie - Dynamics of nucleolus-derived foci throughout the cytoplasm and the disappearance of NDF during telophase
(http://jcb.rupress.org/content/suppl/2000/08/03/150.3.433.F2.DC1) | Movie - Dynamics of nucleolar reassembly in telophase were
analyzed by the visualization of fibrillarin-GFP (http://jcb.rupress.org/content/suppl/2000/08/03/150.3.433.F3.DC1)
Chromosome Features
2 telomeres, centromere, replication origins
Telomere- at ends of chromosome (bacterial DNA circular)
Centromere- holds duplicated DNA together
Kinetochore - protein complex forms around the centromere forms during mitosis
Chromatin - DNA packed by DNA binding proteins (histones and non-histones) form 30nm DNA fibre
2 types of chromatin in interphase nuclei (based on cytology)
heterochromatin - highly condensed (restricted gene transcription)
euchromatin - less condensed (gene transcription)
Telomere
at ends of all chromosomes (not bacterial DNA circular)
roles in chromosome replication and maintenance
replication
for replicating the ends of linear chromosomes
maintenance
proposed to provide each cell with a replication counting mechanism that helps prevent unlimited proliferation
each cell division shortens telomere 50–100 nucleotides
DNA 100s to 1,000s repeats of a simple-sequence containing clusters of G residues (humans AGGGTT)
Telomerase enzyme maintains length
Centromere
directs movement of each chromosome into daughter cells every time a cell divides
centromere embedded in heterochromatin
satellite DNA sequences (AT-rich) repeated many thousands of times
proteins assemble on this to form Kinetochore
attachment site for spindle microtubules
Links: MBOC - Centromere (http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=mboc4.figgrp.672)
Replication Origins
DNA replication initiates at multiple origins (ori)
in both prokaryotic and eukaryotic DNA
multiple origins in eukaryotes (human genome about 30,000 origins)
each origin produces two replication forks (moving in opposite directions)
Chromosome DNA Packing
Euchromatin ("good chromatin") - light, transcriptionally active, about 10% of all
chromatin.
Heterochromatin - condensed, transcriptionally inactive, about 90% of all chromatin.
Nucleosomes
formed by DNA wrapped around histones
unit particle of chromatin (nucleosomal histones) (discovered 1974)
EM unfolded DNA has "beads on a string" appearance
second order folding forms 300 nm fibre
condensed DNA for mitosis 700 nm fibre
Chromosome-condensation
Histones
only in eukaryotes
small proteins positively charged (binds negatively charged DNA)
not sequence specific binding (as in transcription factors)
4 core histones (H2A, H2B, H3, and H4)
2 linker histones (H1/H5)
Abnormalities
Hutchinson-Gilford Progeria Syndrome
In more than 80% of cases the gene defect responsible for HGPS is a single spontaneous mutation in codon 608 of the LMNA gene,
which encodes both lamin A and lamin C
single-base substitution in exon 11 that reveals a cryptic splice site in the LMNA
gene thus producing a truncated protein
progerin is a mutant form of the nuclear architectural protein lamin A
Emery-Dreifuss Muscular Dystrophy
OMIM - LAMIN A/C; LMNA (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?
id=150330)
Loss of a-Type Lamin Expression Compromises Nuclear Envelope Integrity Leading to
Muscular Dystrophy (http://jcb.rupress.org/cgi/content/abstract/147/5/913)
Eukaryote Gene Expression
Nucleosome
DNA -> mRNA -> Protein
DNA (transcription) -> mRNA (translation) -> Protein (function)
DNA -> mRNA splicing (introns removed, exons joined) -> mRNA
DNA -> rRNA, tRNA, siRNA (RNA interference (RNAi) pathway
Nucleus DNA (transcription) -> mRNA Nuclear processing (export) Cytoplasm mRNA
(translation) -> Protein (cytoplasm, rough endoplasmic reticulum)
Protein Modification
Protein - cytoplasmic (free ribosomes), rough endoplasmic reticulum (bound ribosomes)
Hutchinson-Gilford_Progeria_Syndrome
Exocytosis
Rough Endoplasmic Reticulum -> transport vesicle -> Golgi apparatus -> secretory
vesicle
History
Below are some example historical research finding related to cell junctions from the JCB
Archive (http://jcb.rupress.org/misc/fromthearchive.shtml) and other sources.
1961 The nucleolar origin of rRNA (http://jcb.rupress.org/cgi/content/full/168/4/524-a)
Base compositions and half-lives suggest to Jan-Erik Edström that the nucleolus is the
source of rRNA.
References
1. Neveen A Hosny, Mingying Song, John T Connelly, Simon Ameer-Beg, Martin M
Knight, Ann P Wheeler Super-resolution imaging strategies for cell biologists
using a spinning disk microscope. PLoS ONE: 2013, 8(10);e74604 PubMed
24130668 | PLoS One.
(http://www.plosone.org/article/info:doi/10.1371/journal.pone.0074604)
2. Alexander von Appen, Martin Beck Structure Determination of the Nuclear Pore
Complex with Three-Dimensional Cryo electron Microscopy. J. Mol. Biol.:
2016; PubMed 26791760
Textbooks
Molecular Biology of the Cell (4th ed.) - Part 1 Chapter 8 - The Cell Nucleus Three views of a cell membrane (http://www.ncbi.nlm.nih.gov:80/books/bv.fcgi?
db=Books&rid=mboc4.figgrp.1862)
Lamin A EM - normal and KO
Molecular Cell Biology - The Dynamic Cell
(http://www.ncbi.nlm.nih.gov:80/books/bv.fcgi?db=Books&rid=mcb.chapter.145)
The Cell- A Molecular Approach - An Overview of Cells and Cell Research (http://www.ncbi.nlm.nih.gov:80/books/bv.fcgi?
db=Books&rid=cooper.chapter.89)
Search Online Textbooks
"cell nucleus" Molecular Biology of the Cell (http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=cell+nucleus+AND+mboc4%5Bbook%5D) | Molecular Cell Biology
(http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=cell+nucleus+AND+mcb%5Bbook%5D) | The Cell- A molecular Approach
(http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=cell+nucleus+AND+cooper%5Bbook%5D)
"nuclear envelope" Molecular Biology of the Cell (http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=nuclear+envelope+AND+mboc4%5Bbook%5D) | Molecular Cell Biology
(http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=nuclear+envelope+AND+mcb%5Bbook%5D) | The Cell- A molecular Approach
(http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=nuclear+envelope+AND+cooper%5Bbook%5D)
"nuclear pore" Molecular Biology of the Cell (http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=nuclear+pore+AND+mboc4%5Bbook%5D) | Molecular Cell Biology
(http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=nuclear+pore+AND+mcb%5Bbook%5D) | The Cell- A molecular Approach
(http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
db=Books&cmd=search&doptcmdl=DocSum&term=nuclear+pore+AND+cooper%5Bbook%5D)
Books
The Cytoskeleton - cellular architecture and choreography (http://books.google.com/books?id=JNHuxHzTm7IC)
Reviews
Selma Osmanagic-Myers, Thomas Dechat, Roland Foisner Lamins at the crossroads of mechanosignaling. Genes Dev.: 2015, 29(3);225-37
PubMed 25644599
Katherine L Wilson, Scott C Dawson Evolution: functional evolution of nuclear structure. J. Cell Biol.: 2011, 195(2);171-81 PubMed
22006947
Michael D Huber, Larry Gerace The size-wise nucleus: nuclear volume control in eukaryotes. J. Cell Biol.: 2007, 179(4);583-4 PubMed
17998404
Roderick Y H Lim, Ueli Aebi, Birthe Fahrenkrog Towards reconciling structure and function in the nuclear pore complex. Histochem.
Cell Biol.: 2008, 129(2);105-16 PubMed 18228033
Articles
Wenjing Li, Brian J Ferguson, Walid T Khaled, Maxine Tevendale, John Stingl, Valeria Poli, Tina Rich, Paolo Salomoni, Christine J Watson
PML depletion disrupts normal mammary gland development and skews the composition of the mammary luminal cell progenitor
pool. Proc. Natl. Acad. Sci. U.S.A.: 2009, 106(12);4725-30 PubMed 19261859
J Ellenberg, E D Siggia, J E Moreira, C L Smith, J F Presley, H J Worman, J Lippincott-Schwartz Nuclear membrane dynamics and
reassembly in living cells: targeting of an inner nuclear membrane protein in interphase and mitosis. J. Cell Biol.: 1997, 138(6);1193206 PubMed 9298976
L Yang, T Guan, L Gerace Integral membrane proteins of the nuclear envelope are dispersed throughout the endoplasmic reticulum
during mitosis. J. Cell Biol.: 1997, 137(6);1199-210 PubMed 9182656
Acronyms
AA - amino acid
DNA - deoxyribonucleic acid
EM - electron microscopy
FL - flourescent
GEMS - Gemini of coiled bodies
INM - inner nuclear membrane
KASH - Klarsicht/ANC-1/Syne-1 homology domain–containing protein
LEM domain - fold identified in LAP2, emerin, and MAN1 confers direct binding to dsDNA
LINC - nucleoskeleton to the cytoskeleton complexes
mRNA - messenger RNA
NE - nuclear envelope
NES - nuclear export signal
NLS - nuclear localization signal
NPC - nuclear pore complex
NUP - nucleoporin
ONM - outer nuclear membrane
OMIM - Online Mendelian Inheritance in Man Database
PML Bodies - promyelocytic leukaemia nuclear bodies
RER - rough endoplasmic reticulum
RNA - ribonucleic acid
rRNA - ribosomal RNA
SER - smooth endoplasmic reticulum
SUMO - small ubiquitin-related modifier
SUN - Sad1/UNC-84
tRNA - transfer RNA
Movies
Note - JCB has reorganised their website and some of the associated links. Also their Quicktime movies have not been updated and may not
play on current browsers.
Nuclear pore complexes are fixed in place Daigle et al. (http://jcb.rupress.org/cgi/content/abstract/154/1/71) report that nuclear pore
complexes (NPCs) undergo limited movements (http://jcb.rupress.org/cgi/content/full/200101089/F4/DC1) that match the deformations
of the nuclear envelope as tracked using a grid (http://jcb.rupress.org/cgi/content/full/200101089/F4/DC2) of bleached nuclear lamins.
NPCs are therefore remarkably stable complexes, and are probably anchored to a protein network in the nuclear envelope.
Long term FRAP of POM121 - transmembrane nucleoporin
Long term FRAP of lamina B1
NPC movement in interphase
Lamina elasticity (not visible after conversion?)
Nucleoporins reassemble around post-mitotic chromatin A conserved nuclear pore subcomplex was characterized and tracked by
Belgareh et al. (http://jcb.rupress.org/cgi/content/abstract/154/6/1147), who found that the proteins were recruited
(http://jcb.rupress.org/cgi/content/full/154/6/1147/FIG6/DC1) during telophase in a rim pattern surrounding the chromosomes. A low
level of staining was also apparent on the kinetochores throughout mitosis.
Nucleolar re-formation after mitosis Savino et al. (http://jcb.rupress.org/cgi/content/abstract/153/5/1097) follow the re-formation
(http://jcb.rupress.org/cgi/content/full/153/5/1097/F3/DC1) of nucleoli after mitosis. Prenucleolar bodies (PNB) form on the
chromosome surface and nucleolar material flows along links between PNBs
(http://jcb.rupress.org/cgi/content/full/153/5/1097/F4/DC2) and towards (http://jcb.rupress.org/cgi/content/full/153/5/1097/F6/DC1) a
developing nucleolar organizer region (http://jcb.rupress.org/cgi/content/full/153/5/1097/F4/DC1) (NOR). Eventually this leads to the
fusion (http://jcb.rupress.org/cgi/content/full/153/5/1097/F9/DC1) of nucleoli to form a single entity.
Processing complexes may help reassemble nucleoli Nucleolar reassembly (http://jcb.rupress.org/cgi/content/full/150/3/433/F3/DC2)
during telophase is shown by Dundr et al. (http://jcb.rupress.org/cgi/content/abstract/150/3/433) to require mitotically preserved
processing complexes.
Speckles - A splicing factor has limited mobility Based on the limited mobility
(http://jcb.rupress.org/cgi/content/full/150/1/41/F1/DC1) of a splicing factor, Kruhlak et al.
(http://jcb.rupress.org/cgi/content/abstract/150/1/41) determine that the factor undergoes frequent but transient interactions with
relatively immobile nuclear binding sites, both when associated with speckles and when dispersed in the nucleoplasm. This a 3-D video
that should be viewed using red/green 3-D glasses.
2016 Course Content
Lectures: Cell Biology Introduction | Cells Eukaryotes and Prokaryotes | Cell Membranes and Compartments | Cell
Nucleus | Cell Export - Exocytosis | Cell Import - Endocytosis | Cytoskeleton Introduction | Cytoskeleton Microfilaments | Cytoskeleton - Microtubules | Cytoskeleton - Intermediate Filaments | Cell Mitochondria | Cell Junctions
| Extracellular Matrix 1 | Extracellular Matrix 2 | Cell Cycle | Cell Division | Cell Death 1 | Cell Death 2 | Signal 1 | Signal
2 | Stem Cells 1 | Stem Cells 2 | Development | 2016 Revision
Laboratories: Introduction to Lab | Microscopy Methods | Preparation/Fixation | Cell Knockout Methods | Cytoskeleton
Exercise | Immunochemistry | Project Work | Confocal Microscopy | Tissue Culture | Stem Cells Lab | Microarray Visit
Moodle
(http://moodle.telt.
id=18930)
2016 Projects: Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Group 6 | Group 7
Dr Mark Hill 2015, UNSW Cell Biology - UNSW CRICOS Provider Code No. 00098G
Retrieved from "https://cellbiology.med.unsw.edu.au/cellbiology/index.php?title=Cell_Nucleus&oldid=77022"
Categories: Nucleus Organelle Science-Undergraduate 2016ANAT3231
This page was last modified on 15 March 2017, at 23:15.