Term
regulation of gene expression at multiple levels in eukaryotes:
1.
2.
3. |
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Definition
1. transcriptional
2. mRNA processing
3. translational |
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Term
structure of eukaryotic nucleus
- __: differentiates eukaryotes from prokaryotes
- __: ribosome synthesis
-__: dna complexed with protein
- __: materials move in and out of nucleus through these
-__: nuclear cytoskeleton |
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Definition
- nuclear envelope
- nucleolus
- chromatin
- nuclear pore
- nuclear matrix |
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Term
nuclear envelope
- feature of eukaryotic __
- __ membrane
- layers fused at __
- outer membrane continguous with __
- inner membrane lined with __
- chromosomes associated with lamina through __ |
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Definition
- true nucleus
- double layered
- pores
- ER
- lamina matrix (intermediate filament)
- heterochromatin (highly condensed chromatin) |
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Term
Import of nuclear proteins (NLS-containing) into nucleus
- __ containing protein binds __ in cytoplasm
- docks __ extending from outer ring
- stimulates conformation change in central channel __ domains
- __ binds __ subunit to recycle __ to _
- __ returned to cytoplasm by __
- __ is a ras-like monomeric g protein |
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Definition
- nuclear localization sequence (NLS); NLS receptor (importin)
- cytoplasmic filaments
- FG domains
- Ran-GTP; importing beta; importin; cytoplasm
- importin alpha; exportin
- ran |
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Term
transport of mRNAs from nucleus to cytoplasm
- __ complex binds exon-exon junction of __
- __ binding to EJC allows __
- EJC released during __
- non ribosome associated mRNAs containing __ recognized as having premature STOP, undergo __ |
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Definition
- EJC complex; spliced pre-mRNA
- TAP; export
- translation
- EJC; nonsense-mediated decay |
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Term
nucleosome
- ~ 200 bp DNA wrapped around __ core octamer containing 2 each of 2 different heterodimers:histones __/__ and __/__
- __ between __ charged dna backbone and __ charged histones (20-30% __)
- highly conserved __ sequence
- packing ratio __
- __: sites of covalent modifications |
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Definition
- histone; H2A/H2B; H3/H4
- ionic bonds; -; +; (lys/arg)
- amino acid
- 7:1
- N terminal tails |
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Term
- n-terminal covalent modifications give a __ to activity state
-- __: active chromatin
-- __: inactive chromatin
-- __: inactive chromatin
-- __: active chromatin
-- __: mitosis |
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Definition
- histone code
-- acetylation
-- deacetylation
-- methylation (K9h3, K27h3, k2oh4)
-- methylation (K36H3, K4h3)
-- phosphorylation (s10H3) |
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Term
2nd level packaging: __
- increases packing ratio __
- __ array wound into larger diameter fiber
- exact structure still under debate:
1.__: most accepted model
2. random __
- folding requires __ at dna entry and exit points around nucleosome
- __ covalent modifications affect 30 nm fiber folding |
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Definition
30 nm fiber
- 40 fold
- nucleosome
1. solenoid
2. zig zag
- histone h1
- n-terminal |
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Term
3rd level of folding: __
- bases of loops though to be attached to __ |
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Definition
looped domains
- nuclear matrix/scaffold |
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Term
__: dna complexed with protein
- total of __ meters of dna in a typical eukaryotic nucleus with diameter of __
- must be complexed with __ to compact into orderly, accessible structure
- __ level of packaging in metaphase chromosome
- __: metaphase like packaging throughout cell cycle (trascriptionally silent)
- __: metaphase like packaging during mitosis only (transcriptionally competent during interphase) |
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Definition
chromatin
- 2; 10 micrometers
- proteins
- 4th level
- heterochromatin
- euchromatin |
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Term
genes lose __ competency during development
- all cells of the body contain full complement of __ info
- genes are differentially expressed in different __
- all genes are __ in early embryo but lose competency during developmental process
- developmentally regulated facultative __ responsible for loss of competency |
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Definition
transcriptional
- genetic
- tissues
- transcriptionally competent (euchromatic)
- heterochromatin |
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Term
cloning process
- reverse differentiated state of __ cell nucleus (return to totipotency through loss of __)
- nucleus injected into __
- __ formed (without union of egg and sperm: fertilization)
- source of __ for gene therapy |
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Definition
- somatic; (heterochromatin)
- enucleated egg
- diploid zygote
- stem cells |
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Term
| __ es cells can be used in gene therapy |
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Definition
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Term
mammalian embryonic development
- __ > __ > __
- in __ (second above), inner mass cells are __, unrestricted developmental potential
- all genes have a __ organization making them open for transcription
- tissue specific genes become __ in tissues where they are not transcribed |
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Definition
- zygote; blastocyst; gastrula
- blastocyst; pluripotent
- euchromatic
- heterochromatic |
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Term
polytene chomosome squash
- __: more compact (30nm fiber)
- __: less compact (10nm fiber and naked dna) |
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Definition
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Term
nucleosome
- some modifications make tata box more accessible (__), others make it less accessible (__ or __) |
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Definition
| - (active euchromatin); (inactive euchromatin or heterochromatin) |
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Term
Two classes of heterochromatin
- __ (regulated) heterochromatin: developmentally regulated
-- example is __
- __ (unregulated) heterochromatin
-- needed for __ and composed of __
-- examples include __ and __ |
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Definition
- facultative
-- x-chromosome
- constitutive
-- chromosome segregation; repetitive dna
-- centromeres; telomeres |
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Term
- __: attach chromosomes to microtubules in mitosis, __ and __ element of dna
- __: protect chromosome ends from recombination, __ encoded repeats |
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Definition
- centromeres; satellite; transposable
- telomeres; telomerase |
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Term
- 1 of pair of x chromosomes in female mammals is inactivated by __
- __ as to which x becomes heterochromatic during early embryogenesis
- heterochromatin state is __
- initiation of x chromosome inactiviation requires __ which coats x chromosome first expressing it. -maintenance (mitotic memory) due to __ and __ that recruit facultative heterochromatin protein (polycomb) |
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Definition
- facultative heterochromatin
- random decision
- mitotically heritable
- Xist non-coding RNA
- methylation of dna; k27 histone h3 |
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Term
| random x-inactivation in ___ |
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Definition
| early embryo (blastocyst) |
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