2013 Maggio ODONTO Studenti Gurdon Esp ESC

8/12/2019 2013 Maggio ODONTO Studenti Gurdon Esp ESC

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REGOLAZIONE DELL ESPRESSIONE GENICA


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altri meccanismi:

rimodellamento della cromatina

modificazioni post-traduzionali degli istoni

metilazione del DNA

..


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Esperimento di GURDON: trapianto di nucleo da cellula

somatica (pelle) nella cellula uovo non fecondata (1968)


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Figure 8-2b Essential Cell Biology ( Garland Science 2010)

Nelle piante, almeno nella carota, una qualsiasi cellula capace di rigenerare una

pianta.


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Pecora Dolly

1996-2003--telomeri??

--pecora Dolly:caratteristiche della

donatrice di nucleo dellacellula mammaria equalche caratteristicadella madre surrogata


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Figure 8-2c Essential Cell Biology ( Garland Science 2010)

Altri mammiferi .


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Pluripotent, embryonic stem cells originate as innermass cells within a blastocyst. The stem cells canbecome any tissue in the body, excluding a placenta.

Only the morula's cells are totipotent, able to becomeall tissues and a placenta.


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Meccanismi di regolazione dellespressionegenica

fase di morfogenesi

fase di differenziamento

cellule totipotenticellule embrionali pluripotenti

cellule adulte pluripotentiiPSC (induced pluripotent stem cells)


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Sviluppo embrionale

Differenziamento cellulare


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Sviluppo embrionale di Drosophila M.


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Figure 8-13 Essential Cell Biology ( Garland Science 2010)


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Figure 8-23a Essential Cell Biology ( Garland Science 2010)


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Figure 8-23b Essential Cell Biology ( Garland Science 2010)


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Homeodomain fold

The homeodomain fold is a proteinstructural domain that binds DNA or RNA and is

thus commonly found in transcriptionfactors.[2][3]

The fold consists of a 60-amino acid .

Homeodomain folds are found exclusively ineukaryotes.

Many homeodomains induce cellulardifferentiation by initiating the cascades ofcoregulated genes required to produce individual

tissues and organs, while homeodomain proteinslike Nanog are involved in maintaining


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the Antennapediahomeodomain proteinfrom Drosophila melanogasterbound to afragment of DNA.[1] The recognition helix

and unstructured N-terminus are bound in

the major and minor grooves respecti

th h b i t t h f DNA b t 180 l tid l th t


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the homeoboxis a stretch of DNA about 180 nucleotides long thatencodes a homeodomain.Homeobox genes code for homeodomain proteins in both vertebrates

and invertebrates.The existence of homeoboxes was first discovered in Drosophila,where the radical alterations that resulted from mutations in homeoboxgenes were termed homeotic mutations.

The most famous such mutation is Antennapedia, in which legs growfrom the head of a fly instead of the expected antennae.Homeobox genes are critical in the establishment of body axes duringembryogenesis.The consensus 60-polypeptide chain is [1](RRRKRTA-YTRYQLLE-LEKEFLF-NRYLTRRRRIELAHSL-NLTERHIKIWFQN-RRMK-WKKENThe motif is highly conserved over hundreds of millions of years ofevolutionary history, with typically 80% match in the corresponding

nucleotide sequence to the consensus sequence across species,genera and phyla.


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Gene 5 Antennapedia

Gene 6 Bithorax


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2013 Maggio ODONTO Studenti Gurdon Esp ESC

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