Specific and conserved sequences inD. melanogasterandC. eleganslamins and histone H2A mediate the attachment of lamins to chromosomes

Abstract

The intimate association between nuclear lamins and chromatin is thought to regulate higher order chromatin organization. Previous studies have mapped a region between the rod domain and the Ig fold in the tail domain of Drosophila melanogaster lamin Dm0, which binds chromatin in vitro via the histone H2A/H2B dimer. This region contains an evolutionarily conserved nuclear localization signal (NLS) KRKR, and a sequence composed of the amino acids TRAT. Here we show that binding of lamin Dm0 to chromatin requires both NLS and TRAT sequences. Substituting either of the threonine residues in the TRAT sequence with negatively charged residues decreases the binding of lamin Dm0 to chromatin, indicating that this binding could be regulated by phosphorylation. Both lamin Dm0 and C. elegans Ce-lamin bind directly to histone H2A in vitro and this binding requires the NLS. The amino and carboxyl tail domains of histone H2A are each essential, but not sufficient, for binding to lamin Dm0; only a polypeptide containing both histone H2A tail domains binds efficiently to lamin Dm0. Taken together, these results suggest that specific residues in lamin Dm0 and histone H2A mediate the attachment of the nuclear lamina to chromosomes in vivo, which could have implications on the understanding of laminopathic diseases.

Rab5 GTPase controls chromosome alignment through Lamin disassembly and relocation of the NuMA-like protein Mud to the poles during mitosis

“…We confirmed the association of Rab5 with Lamin in reciprocal pulldown experiments using a cell line stably expressing an N-terminal PtA-tagged version of Lamin. In addition to known Lamin interacting proteins such as Otefin (34) and histones (35) (Fig. S3), we also purified Mud and Rab5, confirming that these three proteins are present in a complex in vivo (Fig.…”

Nuclear lamins: major factors in the structural organization and function of the nucleus and chromatin

“…Furthermore, A-type lamins have been identified as conserved peripheral proteins of human metaphase chromosomes (Takata et al 2007). The interaction between the lamins and chromatin appears to involve their non-␣-helical C-terminal tail domain and the N-and C-terminal tail domains of core histones (Hoger et al 1991;Yuan et al 1991;Schmidt and Krohne 1995;Taniura et al 1995;Goldberg et al 1999;Mattout et al 2007). Interestingly, this interaction may also involve the NLS of the lamins (Mattout et al 2007).…”

“…The interaction between the lamins and chromatin appears to involve their non-␣-helical C-terminal tail domain and the N-and C-terminal tail domains of core histones (Hoger et al 1991;Yuan et al 1991;Schmidt and Krohne 1995;Taniura et al 1995;Goldberg et al 1999;Mattout et al 2007). Interestingly, this interaction may also involve the NLS of the lamins (Mattout et al 2007). There are also reports that lamins can bind directly to DNA (Shoeman and Traub 1990;Baricheva et al 1996;Rzepecki et al 1998;Stierle et al 2003) and that this may involve specific sequences in the matrix attachment/scaffold-associated regions (MARs/SARs) (Luderus et al 1994;Zhao et al 1996).…”

Laminopathic mutations interfere with the assembly, localization, and dynamics of nuclear lamins

“…Each of the 14 generated mutants contained a different point mutation was bacterially expressed, purified to near homogeneity (SI Fig. 5A) (18), and used to prepare either filaments or paracrystals as we described in ref. 17.…”