SAGA-CORE subunit Spt7 is required for correct Ubp8 localization, chromatin association and deubiquitinase activity
Background: Histone H2B deubiquitination is performed by numerous deubiquitinases in eukaryotic cells including Ubp8, the catalytic subunit of the tetrameric deubiquitination module (DUBm: Ubp8; Sus1; Sgf11; Sgf73) of the Spt-Ada-Gcn5 acetyltransferase (SAGA). Ubp8 is linked to the rest of SAGA through Sgf73 and is activated by the adaptors Sus1 and Sgf11. It is unknown if DUBm/Ubp8 might also work in a SAGA-independent manner.
Results: Here we report that a tetrameric DUBm is assembled independently of the SAGA-CORE components SPT7, ADA1 and SPT20. In the absence of SPT7, i.e. independent of the SAGA complex, Ubp8 and Sus1 are poorly recruited to SAGA-dependent genes and to chromatin. Notably, cells lacking Spt7 or Ada1, but not Spt20, show lower levels of nuclear Ubp8 than wild type cells, suggesting a possible role for SAGA-CORE subunits in Ubp8 localization. Last, deletion of SPT7 leads to defects in Ubp8 deubiquitinase activity in in vivo and in vitroassays.
Conclusions: Collectively, our studies show that the DUBm tetrameric structure can form without a complete intact SAGA-CORE complex and that it includes full length Sgf73. However, subunits of this SAGA-CORE influence DUBm association with chromatin, its localization and its activity.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
This is a list of supplementary files associated with this preprint. Click to download.
Posted 22 Sep, 2020
On 28 Oct, 2020
On 09 Oct, 2020
Invitations sent on 23 Sep, 2020
On 20 Sep, 2020
On 19 Sep, 2020
On 19 Sep, 2020
On 22 Aug, 2020
Received 13 Aug, 2020
On 30 Jul, 2020
Received 19 Jul, 2020
Invitations sent on 09 Jul, 2020
On 09 Jul, 2020
On 23 Jun, 2020
On 22 Jun, 2020
On 31 May, 2020
On 30 May, 2020
SAGA-CORE subunit Spt7 is required for correct Ubp8 localization, chromatin association and deubiquitinase activity
Posted 22 Sep, 2020
On 28 Oct, 2020
On 09 Oct, 2020
Invitations sent on 23 Sep, 2020
On 20 Sep, 2020
On 19 Sep, 2020
On 19 Sep, 2020
On 22 Aug, 2020
Received 13 Aug, 2020
On 30 Jul, 2020
Received 19 Jul, 2020
Invitations sent on 09 Jul, 2020
On 09 Jul, 2020
On 23 Jun, 2020
On 22 Jun, 2020
On 31 May, 2020
On 30 May, 2020
Background: Histone H2B deubiquitination is performed by numerous deubiquitinases in eukaryotic cells including Ubp8, the catalytic subunit of the tetrameric deubiquitination module (DUBm: Ubp8; Sus1; Sgf11; Sgf73) of the Spt-Ada-Gcn5 acetyltransferase (SAGA). Ubp8 is linked to the rest of SAGA through Sgf73 and is activated by the adaptors Sus1 and Sgf11. It is unknown if DUBm/Ubp8 might also work in a SAGA-independent manner.
Results: Here we report that a tetrameric DUBm is assembled independently of the SAGA-CORE components SPT7, ADA1 and SPT20. In the absence of SPT7, i.e. independent of the SAGA complex, Ubp8 and Sus1 are poorly recruited to SAGA-dependent genes and to chromatin. Notably, cells lacking Spt7 or Ada1, but not Spt20, show lower levels of nuclear Ubp8 than wild type cells, suggesting a possible role for SAGA-CORE subunits in Ubp8 localization. Last, deletion of SPT7 leads to defects in Ubp8 deubiquitinase activity in in vivo and in vitroassays.
Conclusions: Collectively, our studies show that the DUBm tetrameric structure can form without a complete intact SAGA-CORE complex and that it includes full length Sgf73. However, subunits of this SAGA-CORE influence DUBm association with chromatin, its localization and its activity.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5