scholarly journals Macronuclei and micronuclei in Tetrahymena thermophila contain high-mobility-group-like chromosomal proteins containing a highly conserved eleven-amino-acid putative DNA-binding sequence.

1991 ◽  
Vol 11 (1) ◽  
pp. 166-174 ◽  
Author(s):  
I G Schulman ◽  
T Wang ◽  
M Wu ◽  
J Bowen ◽  
R G Cook ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Tetrahymena Thermophila ◽  
High Mobility ◽  
Amino Acid Sequences ◽  
High Mobility Group ◽  
Binding Motif ◽  
Hmg Proteins ◽  
Chromosomal Proteins ◽  
Conserved Sequence

HMG (high-mobility-group protein) B and HMG C are abundant nonhistone chromosomal proteins isolated from Tetrahymena thermophila macronuclei with solubilities, molecular weights, and amino acid compositions like those of vertebrate HMG proteins. Genomic clones encoding each of these proteins have been sequenced. Both are single-copy genes that encode single polyadenylated messages whose amounts are 10 to 15 times greater in growing cells than in starved, nongrowing cells. The derived amino acid sequences of HMG B and HMG C contain a highly conserved sequence, the HMG 1 box, found in vertebrate HMGs 1 and 2, and we speculate that this sequence may represent a novel, previously unrecognized DNA-binding motif in this class of chromosomal proteins. Like HMGs 1 and 2, HMGs B and C contain a high percentage of aromatic amino acids. However, the Tetrahymena HMGs are small, are associated with nucleosome core particles, and can be specifically extracted from macronuclei by elutive intercalation, properties associated with vertebrate HMGs 14 and 17, not HMGs 1 and 2. Thus, it appears that these Tetrahymena proteins have features in common with both of the major subgroups of higher eucaryotic HMG proteins. Surprisingly, a linker histone found exclusively in transcriptionally inactive micronuclei also has several HMG-like characteristics, including the ability to be specifically extracted from nuclei by elutive intercalation and the presence of the HMG 1 box. This finding suggests that at least in T. thermophila, proteins with HMG-like properties are not restricted to regions of transcriptionally active chromatin.

Macronuclei and micronuclei in Tetrahymena thermophila contain high-mobility-group-like chromosomal proteins containing a highly conserved eleven-amino-acid putative DNA-binding sequence

1991 ◽  
Vol 11 (1) ◽  
pp. 166-174
Author(s):  
I G Schulman ◽  
T Wang ◽  
M Wu ◽  
J Bowen ◽  
R G Cook ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Tetrahymena Thermophila ◽  
High Mobility ◽  
Amino Acid Sequences ◽  
High Mobility Group ◽  
Binding Motif ◽  
Hmg Proteins ◽  
Chromosomal Proteins ◽  
Conserved Sequence

HMG (high-mobility-group protein) B and HMG C are abundant nonhistone chromosomal proteins isolated from Tetrahymena thermophila macronuclei with solubilities, molecular weights, and amino acid compositions like those of vertebrate HMG proteins. Genomic clones encoding each of these proteins have been sequenced. Both are single-copy genes that encode single polyadenylated messages whose amounts are 10 to 15 times greater in growing cells than in starved, nongrowing cells. The derived amino acid sequences of HMG B and HMG C contain a highly conserved sequence, the HMG 1 box, found in vertebrate HMGs 1 and 2, and we speculate that this sequence may represent a novel, previously unrecognized DNA-binding motif in this class of chromosomal proteins. Like HMGs 1 and 2, HMGs B and C contain a high percentage of aromatic amino acids. However, the Tetrahymena HMGs are small, are associated with nucleosome core particles, and can be specifically extracted from macronuclei by elutive intercalation, properties associated with vertebrate HMGs 14 and 17, not HMGs 1 and 2. Thus, it appears that these Tetrahymena proteins have features in common with both of the major subgroups of higher eucaryotic HMG proteins. Surprisingly, a linker histone found exclusively in transcriptionally inactive micronuclei also has several HMG-like characteristics, including the ability to be specifically extracted from nuclei by elutive intercalation and the presence of the HMG 1 box. This finding suggests that at least in T. thermophila, proteins with HMG-like properties are not restricted to regions of transcriptionally active chromatin.

scholarly journals The Activity of Mammalian brm/SNF2α Is Dependent on a High-Mobility-Group Protein I/Y-Like DNA Binding Domain

1999 ◽  
Vol 19 (6) ◽  
pp. 3931-3939 ◽  
Author(s):  
Brigitte Bourachot ◽  
Moshe Yaniv ◽  
Christian Muchardt
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
High Mobility ◽  
High Mobility Group ◽  
Binding Motif ◽  
High Mobility Group Protein ◽  
Interaction Domain ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Group Protein

ABSTRACT The mammalian SWI-SNF complex is a chromatin-remodelling machinery involved in the modulation of gene expression. Its activity relies on two closely related ATPases known as brm/SNF2α and BRG-1/SNF2β. These two proteins can cooperate with nuclear receptors for transcriptional activation. In addition, they are involved in the control of cell proliferation, most probably by facilitating p105Rb repression of E2F transcriptional activity. In the present study, we have examined the ability of various brm/SNF2α deletion mutants to reverse the transformed phenotype ofras-transformed fibroblasts. Deletions within the p105Rb LXCXE binding motif or the conserved bromodomain had only a moderate effect. On the other hand, a 49-amino-acid segment, rich in lysines and arginines and located immediately downstream of the p105Rb interaction domain, appeared to be essential in this assay. This region was also required for cooperation of brm/SNF2α with the glucocorticoid receptor in transfection experiments, but only in the context of a reporter construct integrated in the cellular genome. The region has homology to the AT hooks present in high-mobility-group protein I/Y DNA binding domains and is required for the tethering of brm/SNF2α to chromatin.

scholarly journals A high-mobility-group protein and its cDNAs from Drosophila melanogaster.

1992 ◽  
Vol 12 (5) ◽  
pp. 1915-1923 ◽  
Author(s):  
C R Wagner ◽  
K Hamana ◽  
S C Elgin
Keyword(s):  
Drosophila Melanogaster ◽  
Amino Acid ◽  
Acid Content ◽  
Amino Acid Content ◽  
High Mobility ◽  
High Mobility Group ◽  
Chromosome 2 ◽  
Hmg Proteins ◽  
High Mobility Group Protein ◽  
Hmg Protein

We have identified, purified, and characterized a high-mobility-group (HMG) protein and its cDNAs from Drosophila melanogaster. This protein, HMG D, shares most of the characteristics of vertebrate HMG proteins; it is extractable from nuclei with 0.35 M NaCl, is soluble in 5% perchloric acid, is relatively small (molecular weight of 12,000), has both a high basic (24%) and high acidic (24%) amino acid content, and is a DNA-binding protein. HMG D exhibits characteristics of both the vertebrate HMG 1 and 2 class and the HMG 14 and 17 class of proteins. Its amino acid sequence is similar (36% amino acid identity) to that of HMG1, while its size and selective extraction with ethidium bromide are similar to properties of the HMG 14 and 17 class of proteins. HMG D is encoded by a single-copy gene that maps to 57F8-11 on the right arm of chromosome 2. Two transcripts are observed during embryogenesis; the protein is relatively stable throughout development. By the biochemical criteria of size, solubility, and amino acid content, HMG D appears to be the major HMG protein of D. melanogaster.

Purification and characterization of a high-mobility-group-like DNA-binding protein that stimulates rRNA synthesis in vitro

1988 ◽  
Vol 8 (8) ◽  
pp. 3406-3414
Author(s):  
H F Yang-Yen ◽  
L I Rothblum
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
High Mobility ◽  
Dna Binding Protein ◽  
High Mobility Group ◽  
Rrna Synthesis ◽  
Rrna Gene ◽  
Hmg Proteins ◽  
Novikoff Hepatoma

A 16,000-dalton, high-mobility-group-like (HMG-like) DNA-binding protein, referred to as p16, has been purified to homogeneity from Novikoff hepatoma ascites cells. p16 binds specifically to a portion of the 5' flanking region of the rat rRNA gene (-620 to -417), which is part of the upstream activator sequence identified previously (B. G. Cassidy, H.-F. Yang-Yen, and L. I. Rothblum, Mol. Cell. Biol. 6:2766-2773, 1986). p16 also binds to a segment of the external transcribed spacer (+352 to +545). In vitro reconstituted transcription experiments demonstrated that the addition of p16 stimulated rRNA synthesis up to ca. fourfold. The stimulation was dose dependent and saturable. The effect of p16 on ribosomal gene transcription was also dependent on the presence of either the upstream or the downstream DNA-binding site, or both. The amino acid composition of p16 is very similar to that of HMG-I, suggesting that p16 may be a member of the HMG-I family of proteins. In this case, our results suggest that HMG proteins may play an important role in the regulation of the rRNA gene expression.

scholarly journals Comparison of the high-mobility-group chromosomal proteins in rainbow-trout (Salmo gairdnerii) liver and testis

1983 ◽  
Vol 215 (3) ◽  
pp. 531-538 ◽  
Author(s):  
E Brown ◽  
G H Goodwin
Keyword(s):  
Rainbow Trout ◽  
High Mobility ◽  
High Mobility Group ◽  
Hmg Proteins ◽  
Chromosomal Proteins ◽  
Main Fraction ◽  
T1 And T2 ◽  
Protein F

Chromatography and characterization of the proteins extracted by 5% (w/v) HClO4 from rainbow-trout (Salmo gairdnerii) liver and testis show that the two tissues present a characteristically different spectrum of high-mobility-group (HMG) proteins. A variant subfraction of HMG C is found in liver, but is not detectable in testis, where even the main fraction of HMG C is present in only very low quantity. A protein, F, which appears to be related to protein H6 has similarly been isolated only from liver and not from testis. Quantification of the HMG proteins in total 5%-HClO4 extracts of trout liver and testis nuclei shows that, in relation to DNA, levels of HMG T1 and T2, and D are more than 2-fold, and C, 20-fold higher in liver than in testis. However, these differences do not result merely from the sequential withdrawal of HMG proteins at the same time that histones are replaced by protamines in the developing spermatid, since in testis, at some stages of maturation, levels of H6 are almost 2-fold higher than in liver. The implications of these findings for the function of HMG proteins are discussed.

scholarly journals Studies on the tissue specificity of the high-mobility-group non-histone chromosomal proteins from calf

1978 ◽  
Vol 173 (2) ◽  
pp. 497-505 ◽  
Author(s):  
A Rabbani ◽  
G H Goodwin ◽  
E W Johns
Keyword(s):  
Amino Acid ◽  
Gel Electrophoresis ◽  
Trichloroacetic Acid ◽  
Tissue Specificity ◽  
Polyacrylamide Gel Electrophoresis ◽  
High Mobility ◽  
Acid Precipitation ◽  
High Mobility Group ◽  
Chromosomal Proteins ◽  
Calf Thymus

The high-mobility-group (HMG) non-histone chromosomal proteins from calf thymus, liver, spleen and kidney were extracted, and fractionated by CM-Sephadex chromatography and trichloroacetic acid precipitation. The isolated proteins HMG 1, HMG 2 and HMG 17 from the tissues were compared by polyacrylamide-gel electrophoresis, isoelectric focusing and amino acid analysis. The results show that the three proteins are very similar in the tissues studied, implying a lack of tissue specificity.

scholarly journals Characterization and chromatin distribution of the H1 histones and high-mobility-group non-histone chromosomal proteins of trout liver and hepatocellular carcinoma

1991 ◽  
Vol 280 (2) ◽  
pp. 491-497 ◽  
Author(s):  
J R Davie ◽  
G P Delcuve
Keyword(s):  
Gene Expression ◽  
Hepatocellular Carcinoma ◽  
High Mobility ◽  
High Mobility Group ◽  
Hmg Proteins ◽  
Chromosomal Proteins ◽  
H1 Histone ◽  
Liver Chromatin ◽  
And Function ◽  
Liver Hepatocellular Carcinoma

The H1 histones serve as general repressors of gene expression by inducing the formation of a compact chromatin structure, whereas the high-mobility-group (HMG) non-histone chromosomal proteins have roles in maintaining the structure and function of transcriptionally active chromatin. The distribution of the H1 histone subtypes and HMG proteins among various trout tissues (liver, hepatocellular carcinoma, testis and erythrocyte) was determined. Histone H1b was present in the chromatin of liver, but not in the chromatin of hepatocellular carcinoma, testis or erythrocyte. Nuclease-resistant regions of liver chromatin had elevated levels of histone H1b. Histone H1b was isolated, and the N-terminal amino acid sequence of histone H1b was found to be highly similar to that of mammalian histone H1(0) and duck H5. HMG proteins T1, T2, T3, H6, C, D and F were associated with liver and hepatocellular-carcinoma chromatin, with hepatocellular carcinoma containing higher levels of HMG T1 and F. Testis and erythrocyte had HMG T2 and H6 as their predominant HMG proteins. Most of the HMG H6 of hepatocellular carcinoma, but not of liver, was located in a chromatin fraction that was soluble at physiological ionic strength and enriched in transcriptionally active DNA. These alterations in the chromatin distribution and content of hepatocyte HMG proteins and H1 histone subtypes may contribute to aberrant hepatocyte gene expression in the hepatocellular carcinoma.

scholarly journals Purification and characterization of a high-mobility-group-like DNA-binding protein that stimulates rRNA synthesis in vitro.

1988 ◽  
Vol 8 (8) ◽  
pp. 3406-3414 ◽  
Author(s):  
H F Yang-Yen ◽  
L I Rothblum
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
High Mobility ◽  
Dna Binding Protein ◽  
High Mobility Group ◽  
Rrna Synthesis ◽  
Rrna Gene ◽  
Hmg Proteins ◽  
Novikoff Hepatoma

A 16,000-dalton, high-mobility-group-like (HMG-like) DNA-binding protein, referred to as p16, has been purified to homogeneity from Novikoff hepatoma ascites cells. p16 binds specifically to a portion of the 5' flanking region of the rat rRNA gene (-620 to -417), which is part of the upstream activator sequence identified previously (B. G. Cassidy, H.-F. Yang-Yen, and L. I. Rothblum, Mol. Cell. Biol. 6:2766-2773, 1986). p16 also binds to a segment of the external transcribed spacer (+352 to +545). In vitro reconstituted transcription experiments demonstrated that the addition of p16 stimulated rRNA synthesis up to ca. fourfold. The stimulation was dose dependent and saturable. The effect of p16 on ribosomal gene transcription was also dependent on the presence of either the upstream or the downstream DNA-binding site, or both. The amino acid composition of p16 is very similar to that of HMG-I, suggesting that p16 may be a member of the HMG-I family of proteins. In this case, our results suggest that HMG proteins may play an important role in the regulation of the rRNA gene expression.

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