Etudes sur le mécanisme de remodelage des nucléosomes par ...

tel-00413908, version 1 - 7 Sep 2009
INO80 family
Sc INO80 DNA repair
Shen et al., 2000; van Attikum et al., 2004;
Morrison et al., 2004.
Pol II activation
Jonsson et al., 2004.
At INO80
SWR1 family
Homologous recombination
Gene transcription
Fritsch et al., 2004.
Fritsch et al., 2004.
Sc SWR1 Htz1 deposition Mizuguchi et al., 2004; Krogan et al., 2003;
Kobor et al., 2004.
Dm SWR1 DNA repair Kusch et al., 2004.
CHD family
Hs NURD
Ce NURD
Transcriptional repression and
silencing
Development
I.4.3.4.1 Regulation of transcription
63
Wade et al., 1999; Jones et al., 1998.
Unhavaithaya et al., 2002; von Zelewsky et
al., 2000.
SWI/SNF complexes in yeast and mammalian cells are involved in the regulation of
transcription and are recruited to promoters by sequence specific transcription factors (Kadam
and Emerson, 2003; Prochasson et al., 2003). The chromatin remodeling activity then
facilitates binding of both specific and general transcription factors, and it also facilitates the
binding of factors involved in repression, such as HDACs. It is important to recognize that
chromatin remodeling per se does not determine whether transcription will be activated or
repressed, although SWI/SNF activity has so far mostly been associated with activation
several examples of transcriptional repression have also been documented (Moehle and Jones,
1990; Trouche et al., 1997; Moreira and Holmberg, 1999; Murphy et al., 1999). A well
studied aspect of SWI/SNF mediated transcriptional activation is the interaction between
SWI/SNF and nuclear hormone receptors. The GR (glucocorticoid receptor) recruits
SWI/SNF to the MMTV promoter, resulting in increased DNA accessibility that is essential
for transcriptional activation (Fryer and Archer, 1998; Ostlund Farrants et al., 1997). The
complex regulates transcription either directly or via various regulatory proteins e.g. proteins
Pho2 and Pho4 activatetranscription of PHO5 gene (Sudarsanam et al., 2000).
The loss of function mutation of SWI/SNF leads to various different phenotypes including
poor growth, inability to use particular carbon sources, and a defect in sporulation, however, it