Conservation of the MORF4 related gene family: identification of a new chromo domain subfamily and novel protein motif

Bertram, Michael J.; Pereira‐Smith, Olivia M.

doi:10.1016/s0378-1119(01)00372-9

Cited by 83 publications

(108 citation statements)

References 31 publications

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“…We had originally isolated hPAM14 as an MRG-interacting protein in a yeast two-hybrid screen. mMRG15 protein is 100% identical at the amino acid level to hMRG15 (2,31). To confirm that mPAM14 isolated here was indeed an hPAM14 ortholog, we constructed an HAtagged mPAM14 expression plasmid and transfected this with or without a V5-tagged MRG15 expression plasmid into HeLa cells.…”

Section: Isolation and Characterization Of Mpam14 Genomic Clonesmentioning

confidence: 83%

PAM14, a Novel MRG- and Rb-Associated Protein, Is Not Required for Development and T-Cell Function in Mice

Tominaga

Magee

Matzuk

et al. 2004

Molecular and Cellular Biology

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PAM14 has been found to associate in complexes with the MORF4/MRG family of proteins as well as Rb, the tumor suppressor protein. This suggested that it might be involved in cell growth, immortalization, and/or senescence. To elucidate the in vivo function of PAM14, we characterized the expression pattern of mouse Pam14 and generated PAM14-deficient (Pam14 ؊/؊ ) mice. Pam14 was widely expressed in all mouse tissues and as early as 7 days during embryonic development. Despite this ubiquitous expression in wild-type mice, Pam14؊/؊ mice were healthy and fertile. Response to mitogenic stimulation and production of interleukin-2 were the same in stimulated splenic T cells from Pam14 ؊/؊ mice as in control littermates. Cell growth rates of mouse embryonic fibroblasts (MEFs) from all three genotypes were the same, and immortalized cells were obtained from all cell cultures during continuous culture. There was also no difference in expression of growth-related genes in response to serum stimulation in the null versus control MEFs. These data demonstrate that PAM14 is not essential for normal mouse development and cell cycle control. PAM14 likely acts as an adaptor protein in nucleoprotein complexes and is probably compensated for by another functionally redundant protein(s).Replicative senescence, or the state of terminal loss of cell division that normal cells in culture enter after a limited number of replications, is a well-established phenomenon (7,26). This has been proposed to be representative of cellular aging in vivo, as well as a mechanism of tumor suppression. The latter derives from the fact that fusion of normal cells with various immortal cells (capable of indefinite division) yields hybrids that regain growth control and stop dividing, indicating that the senescent phenotype is dominant (21, 23). The immortal cell therefore arises from recessive defects in cell senescence-related genes, and the identification of four complementation groups for indefinite division (A to D) suggests that at least four such pathways exist (22). Microcell-mediated chromosome transfer has led to the identification of loci on human chromosomes 1, 4, and 7 for groups C, B, and D, respectively, as these chromosomes induce specific loss of proliferation in multiple immortal cell lines assigned to the complementation group and have no effect on cell lines assigned to the other groups (30). We cloned a gene on chromosome 4 (MORF4) that had the ability to cause proliferation loss as effectively as the intact chromosome (1) and determined that MORF4 was a member of a family of genes (seven members, three expressed) with motifs predictive of transcription factor activity, most likely as partners in nucleoprotein complexes. To identify potential interacting proteins, we performed a yeast two-hybrid screen with the MORF-related expressed genes MRG15 and MRGX.We obtained a novel cDNA PAM14 (for protein associated with MRG, 14 kDa) that interacts with all three MORF4/ MRG proteins as well as Rb, an important tumor suppressor protein (13). ...

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Section: Isolation and Characterization Of Mpam14 Genomic Clonesmentioning

confidence: 83%

PAM14, a Novel MRG- and Rb-Associated Protein, Is Not Required for Development and T-Cell Function in Mice

Tominaga

Magee

Matzuk

et al. 2004

Molecular and Cellular Biology

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“…1 and 2), and a more distantly related C-terminal MRG domain (9,35). MRG15 also associates with Tip60, a MYST HAT highly similar to MOF as part of a large multiprotein complex that functions in gene regulation and DNA repair through acetylation of histones phospho-H2Av and H4 (9 -13).…”

Section: An Aromatic Cage Methyllysine Binding Pocket In Hmsl3-mentioning

confidence: 99%

“…The Drosophila and human MSL3 proteins contain a highly conserved N-terminal chromo-barrel domain (CBD) (residues 2-91; 50% identical) plus a conserved C-terminal MRG domain (residues 196 -512 in dMSL3; 25% identical to hMSL3) (3,4,(33)(34)(35). The CBD of Drosophila MSL3 is known to contribute to nucleic acid and nucleosome binding in the Drosophila MSL complex (18 -20), transcriptional up-regulation on the Drosophila male X-chromosome (18), and proper targeting and spreading of the dosage compensation complex in vivo (20).…”

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confidence: 99%

“…To better understand the role played by MSL3 in the MSL HAT complex and histone tail recognition, we have undertaken structural and biochemical studies of the highly conserved MSL3 CBD and compared its in vitro histone tail binding to that of the related MRG15 CBD (9,35). After submission of this manuscript, an independent structural and biochemical study on the Drosophila and human MSL3 CBDs was published (36).…”

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confidence: 99%

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Structural and Biochemical Studies on the Chromo-barrel Domain of Male Specific Lethal 3 (MSL3) Reveal a Binding Preference for Mono- or Dimethyllysine 20 on Histone H4

Moore

Ferhatoglu

Jia

et al. 2010

Journal of Biological Chemistry

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We have determined the human male specific lethal 3 (hMSL3) chromo-barrel domain structure by x-ray crystallography to a resolution of 2.5 Å (r ‫؍‬ 0.226, R free ‫؍‬ 0.270). hMSL3 contains a canonical methyllysine binding pocket made up of residues Tyr-31, Phe-56, Trp-59, and Trp-63. A six-residue insertion between strands ␤ 1 and ␤ 2 of the hMSL3 chromobarrel domain directs the side chain of Glu-21 into the methyllysine binding pocket where it hydrogen bonds to the NH group of a bound cyclohexylamino ethanesulfonate buffer molecule, likely mimicking interactions with a histone tail dimethyllysine residue. In vitro binding studies revealed that both the human and Drosophila MSL3 chromo-barrel domains bind preferentially to peptides representing the mono or dimethyl isoform of lysine 20 on the histone H4 N-terminal tail (H4K20Me 1 or H4K20Me 2 ). Mutation of Tyr-31 to Ala in the hMSL3 methyllysine-binding cage resulted in weaker in vitro binding to H4K20Me 1 . The same mutation in the msl3 gene compromised male survival in Drosophila. Combined mutation of Glu-21 and Pro-22 to Ala in hMSL3 resulted in slightly weaker in vitro binding to H4K20Me 1 , but the corresponding msl3 mutation had no effect on male survival in Drosophila. We propose MSL3 plays an important role in targeting the male specific lethal complex to chromatin in both humans and flies by binding to H4K20Me 1 . Binding studies on the related dMRG15 chromo-barrel domain revealed that MRG15 prefers binding to H4K20Me 3 . Nuclear histone acetyltransferase (HAT)3 enzymes are found in multiprotein complexes that acetylate specific lysine residues on the N-terminal tails of histone proteins, thereby regulating nucleosome structure, chromatin packaging, and gene expression (1-15). MOF, a conserved member of the MYST (Moz, Ysb2, Sas2, Tip60) family of HAT enzymes, functions as the catalytic subunit in a number of distinct HAT complexes that target gene promoters (8), large contiguous domains of chromatin (3, 4, 14, 15), or non-histone proteins such as p53 (5-7). The precise targeting and substrate specificity of MOF relies on the presence of components distinct from the catalytic subunit (3,4,7,8). Specifically, in the MOFcontaining Drosophila male specific lethal (MSL) complex, the MSL3 protein is required for chromatin targeting, nucleosome binding, histone tail substrate recognition, and maximal MOF HAT activity (16 -20).The most well studied MOF-containing complex is the Drosophila melanogaster male specific lethal or MSL complex that binds selectively to large regions of the X-chromosome in male flies (14,15,(21)(22)(23)(24)(25)(26) where it is enriched at the 3Ј ends of actively transcribed genes (27-30) and acetylates lysine 16 on histone H4 (H4K16Ac) (22, 31), thereby balancing male Xchromosomal gene expression. The Drosophila MSL complex contains the dMSL1, dMSL2, and dMSL3 proteins, the RNA/ DNA helicase MLE, the HAT enzyme MOF, and one of two apparently functionally redundant non-coding RNAs (roX1 and roX2) (reviewed in Refs. 14, 15, and 21). The...

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“…MRGX 1 is a member of a family of proteins that includes MORF4, a gene that was shown to induce loss of proliferation in a subset of immortal human cell lines (1,2). Genetic analyses that demonstrated that the phenotype of cell senescence (limited division potential exhibited by all normal cells) was dominant over immortality (ability to grow without control) (3) led to the identification of four complementation groups for indefinite division (A-D), suggesting that loss or inactivation of one of four senescence-related pathways resulted in immortalization of human cells (4 -6).…”

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confidence: 99%

MRGX Is a Novel Transcriptional Regulator That Exhibits Activation or Repression of the B-myb Promoter in a Cell Type-dependent Manner

Tominaga¹,

Leung

Rookard³

et al. 2003

Journal of Biological Chemistry

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MRGX is a novel transcription factor that is a member of the mortality factor 4 (MORF4)-related gene family. MRG15, a closely related family member, is in a complex with the retinoblastoma tumor suppressor protein Rb and activates the B-myb promoter, which is tightly controlled by Rb/E2F through the E2F binding site. In this study we investigated the effect of MRGX on the B-myb promoter. Interestingly, MRGX repressed the B-myb promoter in EJ cells (human bladder carcinoma cells), which have a functional Rb, but activated B-myb in HeLa cells (human cervical carcinoma cells), which express a lower amount of Rb. This repression and activation was dependent on the helix-loop-helix and leucine zipper regions of the MRGX protein but not the N-terminal region. MRGX interacts with Rb through the helix-loop-helix and leucine zipper regions. Using a treatment of trichostatin A, which is a potent inhibitor of histone deacetylase (HDAC), we determined that the repression of the B-myb promoter by MRGX in EJ cells was dependent on HDAC activity. We confirmed the association of MRGX with HDAC1 by immunoprecipitation/ Western analysis and determined that MRGX complexes had HDAC activity. The data indicate that MRGX can repress or activate the B-myb promoter depending on the cell type studied, suggesting that there may be tissue-specific functions of this protein.MRGX 1 is a member of a family of proteins that includes MORF4, a gene that was shown to induce loss of proliferation in a subset of immortal human cell lines (1, 2). Genetic analyses that demonstrated that the phenotype of cell senescence (limited division potential exhibited by all normal cells) was dominant over immortality (ability to grow without control) (3) led to the identification of four complementation groups for indefinite division (A-D), suggesting that loss or inactivation of one of four senescence-related pathways resulted in immortalization of human cells (4 -6). Microcell-mediated chromosome transfer identified a normal human chromosome 4 as capable of inducing senescence in immortal cell lines (7) assigned to complementation group B, and subsequently MORF4 was cloned as the gene involved (1). The MORF4/MRG genes comprise a family of seven members; of these, only MORF4, MRGX, and MRG15 are expressed. They share a high degree of similarity and encode motifs such as a leucine zipper (LZ), helixloop-helix (HLH) region, nuclear localization signals, and ATP/ GTP binding domains. MRG15 (amino acids 109 -323) and MRGX (amino acids 74 -288) proteins are 88.8% identical in this common region and most likely associate with similar proteins through this region. MRG15 and MRGX have an additional N-terminal region, and this contains a chromodomain (CHR) motif (8 -15) in the MRG15 protein and a novel sequence in MRGX. We have shown previously that MRG15 interacts with a novel protein PAM14 as well as the Rb protein, in a complex that results in derepression of the B-myb promoter in EJ (bladder carcinoma) cells (16). Deletion mutant constructs indicated that the CHR,...

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Conservation of the MORF4 related gene family: identification of a new chromo domain subfamily and novel protein motif

Cited by 83 publications

References 31 publications

PAM14, a Novel MRG- and Rb-Associated Protein, Is Not Required for Development and T-Cell Function in Mice

PAM14, a Novel MRG- and Rb-Associated Protein, Is Not Required for Development and T-Cell Function in Mice

Structural and Biochemical Studies on the Chromo-barrel Domain of Male Specific Lethal 3 (MSL3) Reveal a Binding Preference for Mono- or Dimethyllysine 20 on Histone H4

MRGX Is a Novel Transcriptional Regulator That Exhibits Activation or Repression of the B-myb Promoter in a Cell Type-dependent Manner

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