A subset of the histone H3 lysine 9 methyltransferases Suv39h1, G9a, GLP, and SETDB1 participate in a multimeric complex
Authors: Lauriane Fritsch
Maya Ameyar-Zazoua
Philippe Robin
Hélène Hinaux
Annick Harel-Bellan
Mouloud Souidi
Claire Rougeulle
Slimane Ait-Si-Ali
Jacques R R Mathieu
Journal: Molecular Cell (2010)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: H3K9; histone methyltransferases; HKMTs; G9a/KMT1C; GLP/KMT1D
Affiliations: Institut André Lwoff, Centre National de la Recherche Scientifique, FRE2944, Université Paris-Sud, 94800 Villejuif, France.

Abstract:  Lysine 9 of histone 3 (H3K9) can be mono-, di-, or trimethylated, inducing distinct effects on gene expression and chromatin compaction. H3K9 methylation can be mediated by several histone methyltransferases (HKMTs) that possess mono-, di-, or trimethylation activities. Here we provide evidence that a subset of each of the main H3K9 HKMTs, G9a/KMT1C, GLP/KMT1D, SETDB1/KMT1E, and Suv39h1/KMT1A, coexist in the same megacomplex. Moreover, in Suv39h or G9a null cells, the remaining HKMTs are destabilized at the protein level, indicating that the integrity of these HKMTs is interdependent. The four HKMTs are recruited to major satellite repeats, a known Suv39h1 genomic target, but also to multiple G9a target genes. Moreover, we report a functional cooperation between the four H3K9 HKMTs in the regulation of known G9a target genes. Altogether, our data identify a H3K9 methylation multimeric complex. 

Retracted: No

PubPeer comments:
 Figure 1. Much more similar than expected. https: imgur.com mLF1IUe , 
 Thank you for your comment. All the endogenous co-IPs and western blots in Figure 1F-H were performed using the same cell extracts and simultaneously. However, given the plethora of antibody combinations used in IP and especially in WB (7 in total), we had to: 1) to perform stripping and reprobing of the WB membranes many times to reveal the different proteins and, 2) used different exposure times for each Ab given their different sensitivities. Thus, as for the G9A and GLP Ctr signals in Fig 1G and 1H, the IgG control (Ctr) is indeed the same, since the co-IP was conducted the same day with the same cell extracts. Thus, we presented the same Ctr signal in Suv39h IP (Fig 1F) and G9A IP (Fig 1G) for G9A and GLP WB signals, but not necessary with the same exposure time (see attached global picture, before slicing). Since the presented WB signals in Suv39h and G9A IPs do not always correspond to the same exposure times, we presented the 2 co-IPs in 2 different panels, F and G. As for Figure 1H, we have indeed sliced the original WB images since the lanes were separated with either empty or non-used lanes. It is not only the SETDB1 IP lane which was sliced (raised in your comment), but also that of Suv39h and GLP IPS. Only the input and the Ctr lanes were contiguous. Please see the attached original images (Suv39h and GLP WB signals are shown as examples) and an annotated autoradiography film to illustrate this. Thus, we have get rid of the non-used lanes and attached the shown lanes to shorten the figure size. We apologize for not having drawn vertical lines to specify that the image was sliced. ![file] We have the ad hoc annotated lab books and all the archives of each single WB and exposure time, and all the intermediary files used to build the final figures. You are welcome to check both the lab book and our WB raw data acquired using the Vilber Lourmat machine. We apologize for any confusion this might have caused. ,