BICD 110 Lecture Notes - Lecture 8: Small Gtpase, Wei Wen, Antigen
28 Jun 2018
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BICD110 Lecture 8 Notes 4/26/18
- The vertebrate nucleus: guarding the fortress of the genome
- Structures that define the eukaryote nucleus
oNuclear envelope
Nuclear membranes: 2
Nuclear lamina: 1
Nuclear pores: 1000s
oChromatin: DNA packaged in nucleosomes using histones
oNucleolus: site of ribosome RNA synthesis and ribosome RNA assembly
ohnRNA: mRNA precursors (before splicing of introns)
oRibosomal RNA precursors
oAbsence of cytoplasmic organelles
oAbsence of cytoplasmic proteins that are > 40kDa
- Functions that define the nucleus
oMolecular biology
DNA replication
DNA recombination and repair
RNA transcription: mRNA, rRNA, tRNA precursors
RNA splicing and modification: mRNA, rRNAs, tRNAs
oCell biology
Nuclear transport (import and export)
Mitosis: disassembly and reassembly of nuclear envelope
- Nuclear envelope
oContains outer and inner nuclear membrane
Outer membrane contiguous with rough ER
Inner nuclear membrane: contains proteins that are
binding sites for the nuclear lamina
oContains nuclear pores, which controls the transport of
substances in and out of nucleus
oContains nuclear lamina: made of lamins (70 kDa, intermediate filament protein family)
Lamin network provides the strength of the nuclear envelope. Need
strength to protect nucleus from lysing
Has 2 genes: Lamin A gene (can also make C) and Lamin B gene
Many diseases are caused by Lamin A gene mutations: laminopathies
Ex: certain muscular dystrophies
Ex: progeria. Hutchinson-Gilford Progeria syndrome (HGPS)
oDescribed by John Hutchinson (1886)
oRare (1 in 4 million)
oSyndrome accelerates aging
oPotentially holds clues to normal aging and atherosclerotic disease
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Document Summary
The vertebrate nucleus: guarding the fortress of the genome. Structures that define the eukaryote nucleus: nuclear envelope. Functions that define the nucleus: molecular biology. Rna splicing and modification: mrna, rrnas, trnas: cell biology. Mitosis: disassembly and reassembly of nuclear envelope. Nuclear envelope: contains outer and inner nuclear membrane. Lamin network provides the strength of the nuclear envelope. Has 2 genes: lamin a gene (can also make c) and lamin b gene. Many diseases are caused by lamin a gene mutations: laminopathies. Nuclear pores that doesn"t protect nuclei: contains cytoplasmic filaments, spokes, and nuclear basket. Fg repeats act as binding sites for importin, transportin, snurportin. Spokes don"t contain fgs, but everywhere else on nuclear pore. How does nuclear transport work: passive diffusion: small molecules like ions and small proteins can enter/exit (<40 kda, receptor-mediated transport: nuclear proteins, newly assembled ribosomes, mrna, trna, histones, dna/rna polymerase, transcription factors can enter/exit.
