Histone Bovine
Description
Fundamental Characteristics of Histone Bovine
Histone bovine is purified from bovine tissues using proprietary protein-chemical techniques. It is characterized as a vastly alkaline protein that exists in eukaryotic cell nuclei, where it sets and directs DNA into structural units called nucleosomes . These proteins are fundamental to chromatin organization and gene expression regulation in eukaryotic cells.
The standard classification of bovine histones includes five key families:
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H1/H5 (linker histones)
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H2A (core histone)
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H2B (core histone)
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H3 (core histone)
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H4 (core histone)
While H2A, H2B, H3, and H4 are considered core histones that form the nucleosome octamer, histones H1/H5 function as linker histones . The dynamics of chromatin structure depend significantly on post-translational modifications of these histones and the appearance of different histone variants. Histone H3 and H4 undergo covalent modifications at several residues, contributing to what is known as the "histone code," alongside H2A/H2B modifications .
Histone Variants and Their Expression in Bovine Systems
Bovine histone variants show distinct expression patterns throughout development, particularly during early embryonic stages. Research has identified multiple histone H3 variants with significant expression patterns in bovine oocytes and embryos.
Expression Patterns of H3 Variants
Among the four annotated H3 variants detected in bovine systems, three (H3F3A, H3F3B, and CENPA) demonstrate high expression levels at various developmental stages. The H3F3A variant shows extraordinarily high expression in oocytes (~12,000 transcripts per million, TPM) but decreases more than 3.8 times after fertilization, maintaining levels around 5,000 TPM during subsequent embryonic development .
Histone Variant Expression Dynamics
Based on comprehensive RNA-Seq analyses of bovine in vivo oocytes and pre-implantation embryos, researchers have identified six distinct expression patterns for histone variants and modifiers:
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Peaked in oocytes but decreased by embryonic genome activation (EGA)
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Transcription before EGA and down-regulated thereafter
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Peaked at EGA
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Activated post-EGA
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Peaked around the morula stage
These dynamic expression patterns highlight the complex temporal regulation of histone variants during bovine early development, suggesting stage-specific functions in chromatin organization and gene expression control.
Post-Translational Modifications of Bovine Histones
Post-translational modifications of histones constitute a critical mechanism for regulating gene expression and chromatin accessibility. In bovine systems, several types of histone modifications have been extensively studied.
Histone Lysine β-hydroxybutyrylation (Kbhb)
Histone Lysine β-hydroxybutyrylation (Kbhb) represents a novel epigenetic post-translational modification identified in bovine tissues in vivo . This modification is caused by the ketone body β-hydroxybutyrate (BHB) and is associated with genes upregulated in starvation-responsive metabolic pathways .
Research has demonstrated that Kbhb is present in multiple bovine tissues, including ovary, cumulus cells, liver, mammary gland, kidney, heart, brain, and fibroblast cultures. This modification specifically occurs at the H3K9 residue (H3K9bhb) and responds robustly to changes in BHB levels .
Dose-Dependent Response of H3K9bhb to BHB Exposure
Studies on bovine fibroblasts have shown that H3K9bhb increases proportionally to BHB exposure in a dose-dependent manner. Cells treated with 2 mM BHB showed approximately 2.56-fold more H3K9bhb staining compared to untreated cells, while treatments with 4 mM and 6 mM BHB resulted in 3.91-fold and 5.22-fold increases, respectively .
Western blot analysis further confirmed these findings, showing 2.27-fold, 4.75-fold, and 6.62-fold increases in cells treated with 2 mM, 4 mM, and 6 mM BHB, respectively, compared to untreated controls . These results suggest that alterations in circulating BHB levels observed during ketosis could significantly influence the bovine epigenome by activating genes responding to metabolic stress.
Histone Methylation in Bovine Systems
Histone methylation represents another critical modification that can substantially alter gene expression patterns. In bovine mammary epithelial cells, methionine (Met) supply affects histone methylation at lysine residues K9 and K27 in histone H3 .
Research using fluorescence resonance energy transfer (FRET) systems has shown that H3K9 demonstrates a more defined response to Met supply than H3K27, with maximal histone methylation observed at 125 μM of Met. This increased histone methylation at H3K9 correlates with higher cellular protein concentration, suggesting functional consequences of this modification .
Profiling Histone Marks in Bovine Development
Comprehensive profiling of histone modifications during bovine preimplantation development has revealed stage-specific patterns and dynamics of various histone marks.
Major Histone Marks in Bovine Embryogenesis
Four major histone marks—H3K4me3, H3K27ac, H3K9me3, and H3K27me3—have been profiled in bovine germinal-vesicle (GV) oocytes and at various embryonic stages including 2-cell, 4-cell, 8-cell, morula, and blastocyst, as well as in inner cell mass (ICM) and trophectoderm (TE) .
Genome-wide profiles of these histone marks revealed two general clustering patterns: pre-embryonic genome activation (EGA) stages (2-, 4-, and 8-cell embryos) and post-EGA stages (morula, blastocysts, ICM, and TE) . This clustering suggests fundamental differences in chromatin organization before and after genome activation during bovine embryonic development.
Broad vs. Narrow Histone Marks
Interestingly, certain histone marks exhibit different distribution patterns at different developmental stages. While H3K4me3 and H3K27ac are typically treated as "narrow" marks in somatic cells, they show broad distributions during early embryonic stages . This observation led researchers to treat H3K4me3 as a broad mark up until the 8-cell stage, reflecting the presence of broad domains of noncanonical H3K4me3 (ncH3K4me3) in bovine oocytes .
Similarly, H3K27ac also shows broad distribution during early stages and was treated as a broad mark until the 8-cell stage for peak-calling purposes . These observations highlight the unique chromatin landscape of early bovine embryos compared to somatic cells.
Cytotoxic Properties of Histone Bovine
Beyond their chromatin-related functions, bovine histones also demonstrate notable cytotoxic properties that have been investigated in various experimental contexts.
Comparative Cytotoxicity Studies
Research comparing the cytotoxicity of bovine histone H1 preparation with recombinant human histones H1 zero and H1.2 on the human leukemia cell line K562 and peripheral blood mononuclear cells (PBMC) from healthy volunteers revealed significant dose-dependent toxicity . In the bovine histone H1 preparation, histone H1.2 was identified as the main compound .
Differential Toxicity of Histone Variants
Among the tested histone preparations, bovine histone preparation and recombinant H1.2 demonstrated stronger cytotoxicities compared to recombinant histone H1 zero . This differential toxicity suggests variant-specific effects that could be relevant for understanding histone functions beyond chromatin organization.
Purified Histone Preparations
Sigma-Aldrich offers purified bovine Histone H1 protein (20 mg) for use as a substrate in histone modification assays, including histone acetyltransferase (HAT), histone deacetylase (HDAC), DNA methyltransferase (DNMT) assays, and chromatin assembly studies . This product, also known as Linker Histone H1, has a molecular weight of approximately 32 kDa .
Detection and Analysis Tools
Assay Genie provides a Bovine Histone H3.3C (H3F3C) ELISA Kit designed to measure Histone H3.3C (H3F3C) in serum, plasma, and other sample types . This sandwich ELISA assay has a detection range of 0.625-40 ng/mL and is specifically reactive to bovine samples .
The dynamic regulation of histone modifications depends on various enzymes that either add or remove specific chemical groups from histone residues.
Distribution of Histone Modifier Transcripts
Analysis of bovine oocytes and pre-implantation embryos has revealed the expression of numerous genes encoding histone-modifying enzymes. From 141 annotated genes, mRNAs for 116 genes were detected (mean TPM >1), with 30 different epigenetic modifiers (25.9%) showing abundant expression (Mean TPM >50) in at least one developmental stage .
The distribution of these modifiers shows that epigenetic regulations in early bovine development appear more diverse via histone variants (10 variants) and histone modification (100 enzymes) than via DNA modifications (6 enzymes) . Among the detected transcripts for histone methylation modifiers, 20.3% (13/64) were abundantly expressed, while a higher percentage of histone acetylation modifiers (27.8%, 10/36) showed abundant expression .
Expression Patterns of Histone Modifiers
Three main expression patterns were identified for histone methyltransferases in bovine embryos:
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Transcription before embryonic genome activation (EGA) and down-regulation thereafter
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Low expression in oocytes but transient increase for EGA
For instance, the histone methyltransferase PRMT1 follows the first pattern, EZH2 exemplifies the second pattern, and SETD3 demonstrates the third pattern . These expression patterns can be altered by in vitro conditions, suggesting environmental influences on epigenetic regulation during bovine development.
Product Specs
Histones are highly alkaline proteins found in the nuclei of eukaryotic cells that package and order DNA into structural units called nucleosomes. There are five main families of histones: H1/H5, H2A, H2B, H3, and H4. H2A, H2B, H3, and H4 are known as core histones, while H1/H5 are referred to as linker histones. The dynamics of chromatin structure are influenced by post-translational modifications of histones and the presence of histone variants. Histones H3 and H4 undergo covalent modification at numerous residues. These modifications, along with those of H2A/H2B, contribute to what is known as the histone code.
Bovine Histone is extracted and purified from bovine tissues using proprietary protein-chemical methods.
Bovine Histone is supplied in a buffer solution of 20mM HEPES (pH 7.6), 250mM NaCl, and 20% glycerol.
The recommended coating concentration ranges from 0.2 to 0.5 µg/ml, depending on the specific type of ELISA plate and coating buffer used. It is suitable for labeling functional groups.
1. Binds to human IgG type autoantibodies.
2. Useful for checkerboard and immunodot analysis for identifying positive and negative samples.
Bovine tissues.
Product Science Overview
Histones are characterized by their high content of lysine and arginine, which contribute to their positive charge. This positive charge allows them to interact with the negatively charged DNA. There are five main types of histones: H1, H2A, H2B, H3, and H4 . These histones form the core around which DNA winds, creating a nucleosome. Each nucleosome consists of a histone octamer, which includes two molecules each of H2A, H2B, H3, and H4, and about 147 base pairs of DNA. The H1 histone, also known as the linker histone, binds to the DNA between nucleosomes, helping to compact the chromatin structure further.
In bovine species, histone variants play significant roles during different stages of development. For instance, the linker histone variant H1FOO is crucial for bovine preimplantation development. It regulates lineage specification and chromatin structure . H1FOO is expressed in oocytes, preimplantation embryos, granulosa cells, and spermatids in cattle. Its depletion leads to developmental arrest, indicating its essential role in early embryonic development.
Histone modifications are critical for regulating gene expression. One such modification is the trimethylation of lysine 4 on histone 3 (H3K4me3), which is associated with gene activation. In bovine oocytes and early embryos, H3K4me3 exhibits a dynamic landscape, with its levels decreasing sharply during embryonic genome activation . This modification is essential for the proper reprogramming of the genome during early development.
Another important modification is histone lysine β-hydroxybutyrylation (Kbhb), which is associated with genes upregulated in starvation-responsive metabolic pathways. This modification has been observed in dairy cows during early lactation, highlighting its role in metabolic regulation .
Understanding bovine histones and their modifications has significant implications for both basic and applied sciences. In agriculture, insights into histone function and regulation can lead to improved breeding strategies and better management of livestock. In biomedical research, bovine histones serve as a model to study chromatin dynamics and gene regulation, providing insights that can be translated to other species, including humans.
