SMART: MBT domain annotation

MBT Present in Drosophila Scm, l(3)mbt, and vertebrate SCML2

SMART accession number:	SM00561
Description:	Present in Drosophila Scm, l(3)mbt, and vertebrate SCML2. These proteins are involved in transcriptional regulation.
Interpro abstract (IPR004092):	The function of the malignant brain tumor (MBT) repeat is unknown, but is found in a number of nuclear proteins involved in transcriptional repression. The repeat contains a completely conserved glutamate at its amino terminus that may be important for function. The crystal structure of the two MBT repeats of human SCM-like 2 protein has been reported. Each repeat consists of an extended "arm" and a globular core. The arm of the first repeat packs against the core of the second repeat and vice versa. The structure of the core-interacting part of each arm consists of an N-terminal alpha-helix and a turn of 3₁₀ helix connected by a short beta-strand. The core consists of an Src homology 3-like five-stranded beta-barrel followed by a C-terminal alpha-helix and another short beta-strand. Each arm interacts with its partner core in a similar way, with the orientation of the N-terminal helix relative to the barrel varying slightly. There are also extensive interactions between the two barrels [(PUBMED:12952983)].
GO process:	regulation of transcription, DNA-dependent (GO:0006355)
GO component:	nucleus (GO:0005634)
Family alignment:	View or

There are 1294 MBT domains in 451 proteins in SMART's nrdb database.

Click on the following links for more information.

Evolution (species in which this domain is found)
Click on to expand nodes. To display all proteins with a MBT domain in a specific node, click on it.

This tree shows only several representative species. The complete taxonomic breakdown of all proteins with MBT domain is also avaliable.

Useful shortcuts: Expand all nodes or Collapse tree
Go to specific node: Anopheles gambiae, Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens, Mus musculus, Rattus norvegicus, Takifugu rubripes
Literature (relevant references for this domain)
Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.
- Usui H, Ichikawa T, Kobayashi K, Kumanishi T
- Cloning of a novel murine gene Sfmbt, Scm-related gene containing four mbt domains, structurally belonging to the Polycomb group of genes.
- Gene. 2000; 248: 127-35
- Display abstract
- A novel cDNA clone encoding a protein structurally related to the transcriptional repressor Polycomb group (PcG) proteins, which regulate homeotic genes and others, was isolated from mouse and rat brain. The coding protein contained the SPM domain and mbt repeats, both of which are characteristic of the PcG proteins, and showed significant similarity in amino acid sequence to the Drosophila Sex comb on midleg (Scm) protein. Since this novel protein contains the mbt repeats in four tandem copies, we designated this murine gene as Sfmbt for Scm-related gene containing four mbt domains. Cloning and characterization of the mouse Sfmbt gene revealed that the coding sequence comprised 20 exons, dispersed along approximately 40kb, and mapped to the proximal part of Chromosome 14. Northern blot analysis showed that the Sfmbt mRNAs were expressed most abundantly in the adult testis, and less intensively in all other tissues examined.
- Wismar J et al.
- The Drosophila melanogaster tumor suppressor gene lethal(3)malignant brain tumor encodes a proline-rich protein with a novel zinc finger.
- Mech Dev. 1995; 53: 141-54
- Display abstract
- The lethal(3)malignant brain tumor [t(3)mbt] gene causes, when mutated, malignant growth of the adult optic neuroblasts and ganglion mother cells in the larval brain and imaginal disc overgrowth. Via overlapping deficiencies a genomic region of approximately 6.0 kb was identified, containing l(3)mbt+ gene sequences. The l(3)mbt+ gene encodes seven transcripts of 5.8 kb, 5.65 kb, 5.35 kb, 5.25 kb, 5.0 kb, 4.4 kb and 1.8 kb. The putative MBT163 protein, encompassing 1477 amino acids, is proline-rich and contains a novel zinc finger. In situ hybridizations of whole mount embryos and larval tissues revealed l(3)mbt+ RNA ubiquitously present in stage 1 embryos and throughout embryonic development in most tissues. In third instar larvae l(3)mbt+ RNA is detected in the adult optic anlagen and the imaginal discs, the tissues directly affected by l(3)mbt mutations, but also in tissues, showing normal development in the mutant, such as the gut, the goblet cells and the hematopoietic organs.
Structure (3D structures containing this domain)

3D Structures of MBT domains in PDB

PDB code	Main view	Title
1oi1		Crystal structure of the mbt domains of human scml2
1oyx		Crystal structure of 3-mbt repeats of lethal (3) malignant brain tumor (seleno-met) at 1.85 angstrom
1oz2		Crystal structure of 3-mbt repeats of lethal (3) malignant brain tumor (native-ii) at 1.55 angstrom
1oz3		Crystal structure of 3-mbt repeats of lethal (3) malignant brain tumor (native-i) at 1.85 angstrom
1wjq		Solution structure of the third mbt domain from human kiaa1798 protein
1wjr		Solution structure of the 2nd mbt domain from human kiaa1617 protein
1wjs		Solution structure of the first mbt domain from human kiaa1798 protein
2biv		Crystal structure of the wild-type mbt domains of human scml2
2eqm		Solution structure of the tudor domain of phd finger protein 20-like 1 [homo sapiens]
2jtf		Solution structure of the phf20l1 mbt domain
2p0k		Crystal structure of scmh1
2pqw		Crystal structure of l3mbtl1 in complex with h4k20me2 (residues 17-25), trigonal form
2r57		Crystal structure of the two mbt repeats from sex-comb on midleg (scm)
2r58		Crystal structure of the two mbt repeats from sex-comb on midleg (scm) in complex with di-methyl lysine
2r5a		Crystal structure of the two mbt repeats from sex-comb on midleg (scm) in complex with methyl lysine
2r5m		Crystal structure of the two mbt repeats from sex-comb on midleg (scm) in complex with peptide r-(me)k-s
2rhi		Crystal structure of the 3-mbt domain from human l3mbtl1 in complex with h1.5k27me2 at 1.66 angstrom
2rhu		Crystal structure of the 3-mbt repeats from human l3mbtl1 bound to dimethyl-lysine and in chimera with histone h3.3(28-34)
2rhx		Crystal structure of the 3-mbt repeats from human l3mbtl1 bound to dimethyl-lysine
2rhy		Crystal structure of the 3-mbt repeats from human l3mbtl1 bound to monomethyl-lysine
2rhz		Crystal structure of the 3-mbt repeats from human l3mbtl1 with d355n point mutation
2ri2		Crystal structure of the 3-mbt repeats from human l3mbtl1 with d355a point mutation
2ri3		Crystal structure of the 3-mbt repeats from human l3mbtl1 with n358q point mutation
2ri5		Crystal structure of the 3-mbt repeats from human l3mbtl1 with n358a point mutation
2rjc		Crystal structure of l3mbtl1 protein in complex with mes
2rjd		Crystal structure of l3mbtl1 protein
2rje		Crystal structure of l3mbtl1 in complex with h4k20me2 (residues 17-25), orthorhombic form ii
2rjf		Crystal structure of l3mbtl1 in complex with h4k20me2 (residues 12-30), orthorhombic form i
2vyt		The mbt repeats of human scml2 bind to peptides containing mono methylated lysine.
3cey		Crystal structure of l3mbtl2
3f70		Crystal structure of l3mbtl2-h4k20me1 complex
3feo		The crystal structure of mbtd1
3h6z		Crystal structure of the four mbt repeats of drosophila melanogaster sfmbt in complex with peptide rhr (me)k vlr

Links (links to other resources describing this domain)
INTERPRO IPR004092