MCB 2050 – Nucleus & Nuclear Transport Vocabulary

Vocabulary flashcards covering key nuclear structure, function, and related concepts from Lectures 1-2.

Genome Sequencing

Determining the complete DNA sequence of an organism’s genome; foundation of post-genomics research.

Functional Genomics

Large-scale study of gene functions and interactions using genomic data and high-throughput approaches.

Autofluorescent Proteins

Naturally fluorescent proteins (e.g., GFP) used to visualize molecules and organelles in living cells.

Cellular Compartmentalization

Segregation of cellular functions into membrane-bound organelles in eukaryotes, enabling greater size and complexity.

Nuclear Compartmentation

Organization of the nucleus into distinct regions (nucleoplasm, matrix, envelope, lamina) for genome regulation.

Nucleoplasm

Fluid interior of the nucleus containing >30 non-membrane subdomains where specific nuclear processes occur.

Nuclear Matrix

Insoluble fibrillar protein network that maintains nuclear shape and anchors subdomains and DNA-processing proteins.

Nuclear Envelope (NE)

Double-membrane structure surrounding the nucleus, composed of nuclear membranes, lamina, and nuclear pores.

Nuclear Lamina

Meshwork of lamin proteins on the inner nuclear membrane providing mechanical support and chromatin attachment.

Nuclear Pore Complex (NPC)

Large, multi-protein channel in the NE that regulates all macromolecular traffic between nucleus and cytoplasm.

Eukaryote

Organism with membrane-bound nucleus and organelles; larger and more complex than prokaryotes.

Prokaryote

Organism lacking a membrane-bound nucleus; DNA resides in a nucleoid with minimal packaging and RNA processing.

Nucleolus

Prominent nuclear subdomain where rDNA is transcribed and initial ribosomal subunit assembly occurs.

Chromosomal Subdomain

Distinct territory occupied by each chromosome during interphase within the nucleus.

Interchromosomal Channels

Spaces between chromosomal subdomains that prevent unwanted DNA interactions and house transcription factories.

Transcription Factory

Site in interchromosomal channels where active genes extend and transcription factors are concentrated.

Kissing Chromosomes

Interchromosomal interaction where regulatory regions from one chromosome activate genes on another.

Nuclear Speckles

Dynamic nuclear subdomains rich in mRNA splicing factors located near transcription factories.

Inner Nuclear Membrane (INM)

Innermost phospholipid bilayer of the NE with a unique protein composition distinct from the outer membrane.

Outer Nuclear Membrane (ONM)

Outer bilayer of the NE continuous with rough ER and studded with cytoplasmic ribosomes.

Nuclear Envelope Lumen

10–50 nm space between INM and ONM that is continuous with the ER lumen.

Lamin A

Type-A lamin whose mutation can destabilize the lamina, causing nuclear defects.

Hutchinson-Gilford Progeria Syndrome

Premature-aging disease caused by a point mutation in the LAMIN A gene producing a truncated lamin protein.

Nucleoporin (Nup)

Protein component of the NPC; ~40 different Nups form the complex’s scaffold and peripheral structures.

FG Nucleoporins

Nups with phenylalanine–glycine (FG) repeats that form a disordered mesh limiting passive diffusion (>40 kDa).

Central Scaffold (of NPC)

Integral-membrane Nup assembly anchoring the NPC in the NE and forming the central aqueous channel.

Y-Complex

Structural Nup assembly forming cytoplasmic and nuclear rings that link to other NPC structures.

Cytoplasmic Filaments

Filamentous Nups extending into the cytoplasm to capture import cargo–receptor complexes.

Nuclear Basket

Basket-shaped Nup assembly on the nucleoplasmic side involved in cargo import and RNA export.

Size-Exclusion Limit (NPC)

Approximate 40 kDa threshold above which macromolecules require active transport through the NPC.

Transcription Factor

Protein that binds DNA to regulate transcription; nuclear access is controlled by the nuclear envelope.

Ribosome Biogenesis

Production of ribosomal subunits beginning in the nucleolus and completed in the cytoplasm.

Compartmentalized Gene Regulation

Spatial and temporal control of gene expression afforded by separating transcription (nucleus) and translation (cytoplasm).

Rough Endoplasmic Reticulum (RER)

Organelle continuous with the ONM; covered with ribosomes for co-translational protein synthesis.

Stem Cells

Undifferentiated cells capable of self-renewal and giving rise to specialized cell types; studied in regeneration biology.