Cell Nucleus: Composition,Functions,Sub Nuclear Bodies & Latest Research Trends

1. Topic: Nucleus
Presented by: D.Sairam
Course: Life Science: Fundamentals of
Biology
Course Code:BSBT-201
Course Instructor: Dr.Subhabrata Kar
Presentation Code: U1P1

2. Overview
 Introduction
 History
 Composition
 Functions
 Recent Revelations
 References

3. Introduction
• Eukaryotic Membrane Based Organelle
• Comprises of Linear DNA molecules.
• Monitors Cellular Activity by Gene Regulation.
• Enclosed in a Double Membrane Envelope
• Comprises of Pores to allow Transport of
Molecules.
• Largest Cell Organelle in Animals
• Comprises of Viscous Fluid (Nucleoplasm)
throughout the Organelle

5. Discovery of Nucleus
• It was discovered by A .V Leeuwenhoek for first
time.
• Franz Bauer in 1802 also described it
• Scottish botanist Robert Brown explained it in more
detail.
• Later it was concluded that it is a membrane
bounded organelle found in eukaryotic cells

6. Composition of Nucleus
 Nuclear membrane.
 Nuclear pores.
 Nuclear lamina.
 Chromosomes.
 Nucleolus
 Other Sub Nuclear Bodies ( Cajal
Bodies,PML,Speckles etc.)

7. Nuclear Membrane
 Comprises of Two Membranes i.e. Inner and
Outer. ( 10 to 50 nm Separation)
 Encloses the Nucleus; Prevents diffusion of
Macromolecules.
 Outer Membrane continuous with RER
studded with Ribosomes.
 Space between the two Membranes is called
Perinuclear Space.

9. Nuclear Pores
• Eightfold-symmetric ring-shaped structures.
• 3000-4000 in number and 9 nm wide.
• Allow Selective passage of small water
soluble molecules.

10. Nuclear Lamina
 Organised Network of Filaments inside the Nuclear
Envelope.
Provide Structural support for the Nuclear Envelope
systems provide structural support for the nuclear
envelope.
 Comprise of Lamin Proteins

11. Chromosomes
• DNA inside the Nucleus organised to form
Chromosomes.
• Comprises of a matrix called Chromatin.
• Euchromatin: Contains genes that are frequently
used.
• Heterochromatin: Contains Genes that are
Infrequently Transcribed.

13. Nucleolus
It is a discrete densely stained structure found in
the nucleus.
 Main role is to synthesize rRNA in NOR.
 Cohesion and Density of the Nucleolus relies on
the activity of rRNA synthesis.

14. • FC:Fibrilliar
Centres
• DFCs : Dense
Fibrilliar
Centres
• GC: Granular
Centres

15. Other Subcellular Bodies
 Cajal Bodies: Circular Coiled bodies
performing different Functions related to RNA
Processing.
 PML Bodies: Comprise of Promyelocytic
Leukaemia protein. It plays a vital role in
assembling Nuclear Bodies. Absent in Mice.
 Speckles: Enriched in mRNA factors. Serve as
a model for studying Gene Expression.

17. Recent Revelations about the Nucleus
 Mutations in Lamin genes leads to Laminopathies (
e.g. Progeria).
 IQGAP1 protein helps in Amplification of Cancer
Cells.
 Dicer is a protein forms RISC (RNA Induced
Silencing Complex) and plays a vital role in RNAi

18. Progeria: Leads to
Premature Aging
as seen here.

19. References
• www.uniprot.org/uniprot/Q9UPY3
• www. cancerres.aacrjournals.org/content/66/18/9074.ful
• www.biology4kids.com/files/cell_nucleus.html
• www.ck12.org/biology/Cell-Nucleus/lesson/Cell-Nucleus/
• www.ncbi.nlm.nih.org/220818899
• www.jcb.rupress.org/content/148/2/283.full.pdf
• www.sciencedirect.com/science/article/pii/S016748890800267X
•