The yeast mitochondrial RNA polymerase (RNAP) is a two-subunit enzyme composed of a catalytic core (Rpo41) and a specificity factor (Mtf1) encoded by nuclear genes []. Though related to RNA methyltransferases, Mtf1 might be a functional analogue of the bacterial initiation factor sigma []. This group represents Mtf1 (mitochondrial transcription factor 1).
High mobility group (HMG) box domains are involved in binding DNA, and may be involved in protein-protein interactions as well. The structure of the HMG-box domain consists of three helices in an irregular array. HMG-box domains are found in one or more copies in HMG-box proteins, which form a large, diverse family involved in the regulation of DNA-dependent processes such as transcription, replication, and strand repair, all of which require the bending and unwinding of chromatin. Many of these proteins are regulators of gene expression. HMG-box proteins are found in a variety of eukaryotic organisms, and can be broadly divided into two groups, based on sequence-dependent and sequence-independent DNA recognition; the former usually contain one HMG-box motif, while the latter can contain multiple HMG-box motifs.HMG-box domains can be found in single or multiple copies in the following protein classes: HMG1 and HMG2 non-histone components of chromatin; SRY (sex determining region Y protein) involved in differential gonadogenesis; the SOX family of transcription factors []; sequence-specific LEF1 (lymphoid enhancer binding factor 1) and TCF-1 (T-cell factor 1) involved in regulation of organogenesis and thymocyte differentiation []; structure-specific recognition protein SSRP involved in transcription and replication; MTF1 mitochondrial transcription factor; nucleolar transcription factors UBF 1/2 (upstream binding factor) involved in transcription by RNA polymerase I; Abf2 yeast ARS-binding factor []; yeast transcription factors lxr1, Rox1, Nhp6b and Spp41; mating type proteins (MAT) involved in the sexual reproduction of fungi []; and the YABBY plant-specific transcription factors.
High mobility group (HMG) box domains are involved in binding DNA, and may be involved in protein-protein interactions as well. The structure of the HMG-box domain consists of three helices in an irregular array. HMG-box domains are found in one or more copies in HMG-box proteins, which form a large, diverse family involved in the regulation of DNA-dependent processes such as transcription, replication, and strand repair, all of which require the bending and unwinding of chromatin. Many of these proteins are regulators of gene expression. HMG-box proteins are found in a variety of eukaryotic organisms, and can be broadly divided into two groups, based on sequence-dependent and sequence-independent DNA recognition; the former usually contain one HMG-box motif, while the latter can contain multiple HMG-box motifs.HMG-box domains can be found in single or multiple copies in the following protein classes: HMG1 and HMG2 non-histone components of chromatin; SRY (sex determining region Y protein) involved in differential gonadogenesis; the SOX family of transcription factors []; sequence-specific LEF1 (lymphoid enhancer binding factor 1) and TCF-1 (T-cell factor 1) involved in regulation of organogenesis and thymocyte differentiation []; structure-specific recognition protein SSRP involved in transcription and replication; MTF1 mitochondrial transcription factor; nucleolar transcription factors UBF 1/2 (upstream binding factor) involved in transcription by RNA polymerase I; Abf2 yeast ARS-binding factor []; yeast transcription factors lxr1, Rox1, Nhp6b and Spp41; mating type proteins (MAT) involved in the sexual reproduction of fungi []; and the YABBY plant-specific transcription factors. Structurally, the HMG box domain is composed of three helices.
