| Primary Identifier | IPR003655 | Type | Domain |
| Short Name | aKRAB |
| description | This domain of about 70 amino acid residues is related to the Krueppel-associated box (KRAB) domain and has been recently stratified as the ancestral KRAB domain (aKRAB). Sequence analysis revealed that these sequences have a motif that can also be traced in invertebrates, whose homologues still exist in mammals, including humans, in the PR/SET domain 9 (PRDM9) and synovial sarcoma X breakpoint (SSX) orthologous and paralogous groups []. This domain is found in the N-terminal ends of PRDM9 and proteins belonging to the SSX family [, , ]. Proteins of the SSX family lack the C2H2-type zinc finger which is invariably found in proteins containing the KRAB domain.Although the aKRAB domains of SSX1 and SSX2 contribute to the repressive activity of these proteins, transcriptional repression is mainly mediated by an auxiliary region located in their C terminus, called KRAB-B []. Hence, unlike the canonical KRAB domain, the aKRAB domain is only a weak transcriptional repression domain, as seen in human PRDM9, which neither silences transcription nor interacts with TRIM28/KAP1 [, ]. |
