|A. Summary||B. Nomenclature Changes||C. Literature Search Strategy||D. HMG Families||E. Canonical and Mammalian HMGs||F. Various HMGs||G. Plant HMGs|
|The High Mobility Group (HMG) proteins were originally isolated from mammalian cells, named according to their electrophoretic mobility in polyacrylamide gels, and arbitrarily classed as a specific type of nonhistone proteins based on the observation that they are ubiquitous to mammalian cells, that they share certain physical properties, and that they are associated with isolated chromatin. These mammalian proteins are considered to be Canonical HMG proteins and are now subdivided into 3 families: the HMGB (formerly HMG-1/-2) family, the HMGN (formerly HMG-14/-17) family, and the HMGA (formerly HMG-I/Y/C) family. Each HMG family has a characteristic functional sequence motif. The functional motif of the HMGB family is called the "HMG-box;" that of the HMGN family, the "nucleosomal binding domain;" and that of the HMGA family, the "AT-hook." The functional motifs characteristic of these canonical HMGs are widespread among nuclear proteins in a variety of organisms. Proteins containing any of these functional motifs embedded in their sequence are known as "HMG motif proteins."|
|The New Nomenclature establishes a set of rules and a systematic way to name the genes and proteins belonging to the High Mobility Group (HMG) families of nuclear proteins. The HMG proteins are now subdivided into three families named HMGB, HMGA, and HMGN. The names of the genes correspond to the names of the encoded proteins. Within a family, the genes are named in sequential order (e.g., HMGB1, HMGB2). Splice variants are indicated by small letters (e.g., HMGA1a, HMGA1b and HMGA1c). The nomenclature has been devised to solve certain problems in mammalian genetic nomenclature; however the rules can be extended to other organisms. The new nomenclature now allows for a rational and complete search of the literature pertaining to HMG nuclear proteins. The interrelationship between the various mammalian HMG proteins is diagrammed below.|
|Concomitant with the name changes, the search methods for HMG proteins have been modified in PubMed (ENTREZ) and alterations will be made in the MESH indexing. The old and new HMG names are both forward and backward search compatible. Thus, a PubMed search with a new term, "HMGB1", now, and in the future, will give the same result as a search with any of the old terms such as HMG1, HMG-1 or amphoterin. In the future, a search with HMG-14 will still give all the entries with text words such as either HMG-14, HMG14, or HMGN1 (see Table of HMG Proteins). A search with HMGB, HMGN, or HMGA will yield entries for all the members of that HMG family. These options were not available prior to the name change and a search with the term "HMG" would have yielded many hits, >70% of them not related to the canonical HMG nuclear proteins. Note that the old search strategy is still available and may be useful for certain searches.|
|I.||The HMGB and HMG-Box Proteins. The main identifying functional symbol (root symbol) for canonical proteins of this type is HMGB. Canonical HMGB proteins typically contain TWO HMG boxes, box A and box B. HMGB related motifs are found in many mammalian and non-mammalian proteins (e.g., SRY contains an HMG box motif embedded in its primary sequence). These HMG motif proteins are referred to as HMG-Box proteins and not HMGB proteins. The nomenclature for non-canonical HMG-Box proteins is not covered under this revision.|
|II.||The HMGN Family and HMG-Nucleosome Binding Protein Families. The main identifying functional symbol (root symbol) for canonical proteins of this type is HMGN. Canonical HMGN proteins typically contain nucleosome binding domain. HMGN related motifs are also found in other mammalian proteins (e.g., NSBP-1 contains an HMGN box motif embedded in its primary sequence). The nomenclature for non-canonical HMG-Nucleosome Binding proteins is not covered under this revision.|
|III.||The HMGA Family and HMG-AT-Hook Protein Families. The main identifying functional symbol (root symbol) for canonical proteins of this type is HMGA. Canonical HMGA proteins typically contain two or three AT hooks. HMGA related motifs are found in many mammalian and non-mammalian proteins. These HMGA motif proteins are referred to as HMG-AT-hook proteins and not HMGA proteins. The nomenclature for non-canonical HMG-AT-hook proteins is not covered under this revision.|
|Table of HMG Proteins|
|Protein, New Name||Protein, Old (Alternate) Name||Gene, New Symbol||*Accession #|
|HMGB1||HMG1; HMG-1;HMG 1; (amphoterin)||HMGB1
|HMGB2||HMG2; HMG-2; HMG 2||HMGB2
|HMGB3||HMG2a; HMG-2a; HMG 2a (HMG-4)||HMGB3
|HMGB4**||New, no protein characterized yet.||**127540 (intronless)|
|HMGN1||HMG-14; HMG14; HMG 14||HMGN1
|HMGN2||HMG-17; HMG17; HMG 17||HMGN2
|HMGA1a||HMG-I; HMGI; HMG I
|HMGA1b||HMG-Y; HMGY; HMG Y||HMGA1
|Examples of other HMG Proteins, OLD nomenclature (incomplete list). These examples are not included with the text search results using the above terms, but many can be identified through sequence search strategies.|
|HMG20||Later identified as ubiquitin.
Not an HMG protein.
|HMG20A||Recently discovered factor. |
Not a canonical HMG protein.
|HMG20B||Recently discovered factor.
Not a canonical HMG protein
|HMG-6 (H6)||HMGN protein from Trout.||T: g70781|
|HMG-E||HMGB protein originally from erythrocytes||None|
|HMG-14a,b||HMGN variants of chicken.|
|HMG-D||Drosophila protein related to HMGB.||D: X71138|
|HMG-T1,2,3||HMGB proteins from Trout.||T: X02666 and L32859|
|HMG-X||HMGB type from Xenopus.||X: D30765|
|HMG-3||Degradation product of HMGB1.||None|
|HMG-4||Recently described protein identical to HMGB3.||H: NP_005333
|HMG-2a||HMGB variant from chicken, named differently than those from human, mouse, or calf.||C: X63463|
|HMG-2b||HMGB variant from human with novel 3' UTR.||H: Z17240|
|Protein, New Name||Protein, Old (Alternate) Name||Remark||*Accession#|
|HMGB1||HMGa||HMGB type protein from maize (Zea mays)||X58282|
|HMGB2||HMGc1||HMGB type protein from maize (Zea mays)||Y08297|
|HMGB3||HMGc2||HMGB type protein from maize (Zea mays)||Y08298|
|HMGB4||HMGd||HMGB type protein from maize (Zea mays)||Y08807|
|HMGB5||HMGe||HMGB type protein from maize (Zea mays)||AJ006708|
|HMGA||HMGI/Y||HMGA type protein from maize (Zea mays)||AJ131371|
|HMGB1||HMGa||HMGB type protein from Arabidopsis thaliana||Y14071|
|HMGB2||HMGb1||HMGB type protein from Arabidopsis thaliana||Y14072|
|HMGB3||HMGb2||HMGB type protein from Arabidopsis thaliana||Y14073|
|HMGB4||HMGg||HMGB type protein from Arabidopsis thaliana||Y14074|
|HMGB5||HMGd||HMGB type protein from Arabidopsis thaliana||Y14075|
|* The accession is the unique identifier to either the GenBank record containing the gene sequence encoding that protein or
to the "reference
sequence" (https://www.ncbi.nlm.nih.gov/RefSeq/) as assigned
by GenBank. The accession # used does not imply any priority of discovery
or scientific significance.
(1) Denotes full length gene coding for the HMGA1 proteins.
The tables were compiled by several investigators.
This Web site is maintained by the Mouse Gene Nomenclature Committee.
Suggestions, remarks, corrections, or questions can be addressed to firstname.lastname@example.org.