What protein does the transcription factor regulated by gene expression in eukaryotic cells belong t

It is a group of protein molecules that can specifically bind to a specific sequence upstream of the 5 ends of the gene, so as to ensure that the target gene is expressed at a specific intensity at a specific time and space.

Transcription factors are a group of protein molecules that can bind specifically to a specific sequence upstream of the 5th end of a gene, so as to ensure that the target gene is expressed at a specific intensity in a specific time and space.

A transcription factor is a protein molecule with a special structure that regulates gene expression, also known as a trans-acting factor. There are two types of transcription factors in plants, one is a non-specific transcription factor that non-selectively regulates the transcriptional expression of genes, such as HvcbF2 (C-repeat dre binding factor 2) in barley (Hordeum vulgare) (Xue et al.)., 2003)。

There is also a type of transcription factor, called idiome, which selectively regulates the transcriptional expression of one or more genes. Typical transcription factors contain functional regions such as DNA-binding domains, activation domains, oligomerization sites, and nuclear localization signals. These functional regions determine the function and properties of transcription factors (Liu et al.).

1999)。The main structures of DNA binding zone commonality are: 1) HTH and HLH structures

It is composed of two sections-spiral clamping a section-folding, and the spiral and -fold are connected by a -corner or a ring, that is, a spiral-corner-helix structure and a helix-ring-helix structure. 2) Zinc finger structure: Mostly found in TFIII A and steroid hormone receptors, it is composed of a cysteine-rich polypeptide chain.

Each of the four hemiphotoamidine residues or histidine residues chelates the molecule Zn2+, while the remaining approximately 12-13 residues protrude finger-like and bind to the groove of the DNA double helix. 3) Leucine zipper structure: it is mostly seen at the C-terminus of eukaryotic DNA-binding proteins and is related to the regulation of oncogene expression.

It is composed of two segments of -helix arranged in parallel, in which there are leucine residues arranged regularly every 7 residues, the leucine side chains are arranged alternately in a zipper shape, and the two peptide chains are clamped to bind to DNA.

Similarities: Transcription initiation is a key link in the regulation of gene expression2Differences:

a.The expression regulation of prokaryotic genes mainly includes transcription and translation levels The expression regulation of eukaryotic genes mainly includes chromatin activation, transcription, post-transcriptional processing, translation, and post-translational processingThe regulation of prokaryotic gene expression is mainly negatively regulated, and eukaryotic is mainly positively regulated

Prokaryotic transcription does not require transcription factors, RNA polymerase directly binds to the promoter, and the specificity of the gene table is determined by SITA factors Transcription initiation of eukaryotic genes requires two types of transcription factors that are basally specific Dependent on DNA-protein and protein-protein interactions Regulate transcriptional activationProkaryotic gene expression regulation mainly uses operon model to transcribe polycistronic RNA to achieve coordinated regulation Eukaryotic gene transcription products are monocistronic RNA function-related proteins, and the coordinated expression mechanism of protein-related proteins is more complex. The regulation of gene expression in eukaryotes is mainly at the transcriptional level, followed by the translational level.

Prokaryotic genes exist in the form of operons. Transcriptional level regulation involves promoters, SITA factors binding to RNA polymerase, negative regulation of repressor proteins, positive regulatory proteins, inverted proteins, RNA polymerase inhibitors, attenuators, etc. The regulation of translation level involves the regulation of SD sequence, mRNA stability (the hairpin structure at the 5' and 3' ends can protect the 5' end from being hydrolyzed by enzymes, and the binding of the 5' end of mRNA to ribosomes can significantly improve stability), translation products, and small RNA molecules.

At the DNA level, gene expression can be affected by chromosome loss, gene amplification, gene rearrangement, DNA methylation, and chromosome structure changes. At the transcriptional level, the binding of transcription factors to TATA cassette, the binding of RNA polymerase to transcription factor-DNA complexes, and the formation of transcription initiation complexes are mainly regulated by trans acting factors. Gene expression is mainly affected by RNA modification, splicing, and control of mRNA trafficking at the post-transcriptional level.

At the translation level, there are repressor proteins that affect initiation translation, 5' AUG, 5' non-coding region length, regulation of mRNA stability, and small RNA molecules. The most important link in eukaryotic gene regulation is gene transcription Eukaryotic gene expression requires transcription factors, promoters, silencers, and enhancers.

The regulation of gene expression in eukaryotes is much more complex than in prokaryotes and can occur at a variety of different levels, such as DNA level, transcriptional level, post-transcriptional modification, translational level, and post-translational modification (possible regulatory links in eukaryotic gene expression). However, the most economical and major regulatory link is still at the transcriptional level.

Regulation at the DNA level controls gene expression by changing the number, structural sequence, and activity of relevant genes in the genome. Regulatory mechanisms in this category include amplification, rearrangement, or chemical modification of genes. Some of these changes are reversible.

The most important feature of the expression regulation of prokaryotic genes is the operon pattern, which is mainly at the transcription level, that is, the regulation of RNA synthesis, followed by the translation level. There are usually two ways: initiation regulation, i.e., promoter regulation; Termination regulation, i.e., attenuator regulation.

Regulatory mechanism of prokaryotic genome: through the compound regulation of negative and positive regulatory factors, the binding of repressor proteins to manipulated genes hinders the binding of RNApol and P to form open promoter complexes and prevents gene transcription; When the repressor protein dissociates from the operon gene, the RNA polymerase binds to the promoter, and the initiation gene is transcribed, transcription initiation regulation: factors control the expression of specific genes, different factors can compete to bind RNA polymerase, and the core enzyme of RNA polymerase recognizes the promoters of different genes with holoenzymes composed of different factors.

Lactose operon is the most typical mode of gene transcriptional regulation in prokaryotes, and the transcriptional regulation mechanism of lactose operon: compound regulation through positive and negative regulators. Inhibitory proteins bind to operon genes, preventing RNApol from binding to P to form an open promoter complex and preventing gene transcription. The binding of CAP to the CAP binding site promotes the binding of RNApol to P, resulting in efficient transcription.

Two conditions are required for gene transcription of lactose operon structure genes: a. repressor protein dissociates from manipulative genes b. CAP binds to CAP binding sites. (Transcriptional regulation of arabinose operon, transcriptional regulation of tryptophan operon) Regulation of transcriptional termination:

There are two main categories of transcriptional termination regulation in prokaryotes: factor-dependent and factor-independent termination regulation; Regulation of translation level: the influence of the order and position of the SD sequence on translation, the SD sequence is a nucleotide sequence composed of 3-9 bases upstream of the mRNA start codon AUG, which is the ribosomal binding site.

The regulation of the expression of prokaryotic genes mainly includes transcription and translational levels.

The regulation of prokaryotic gene expression is mainly negatively regulated.

Prokaryotic transcription does not require transcription factors, RNA polymerase binds directly to the promoter, and SITA factors determine the specificity of the gene table.

Prokaryotic gene expression regulation mainly uses the operon model, and polycistronic RNA is transcribed to achieve coordinated regulation.

Transcription is the process by which genetic information is converted from DNA to RNA. As the first step in protein biosynthesis, transcription is the synthesis step of mRNA as well as non-coding RNA (tRNA, rRNA, etc.).

1.Although there are also multiple levels of regulation, it is mainly at the transcriptional level.

2.It is mostly controlled by manipulator submodels. Because most of the genes of prokaryotes are clustered and densely packed on chromosomes according to functional correlation, and together form a transcription unit - operon.

3.Negative regulation is the main mode.

Answer]: Regulation of gene expression in eukaryotes at the transcriptional level:

Gene transcription in eukaryotes is regulated by ampero-luci-acting elements and trans-acting factors.

1) The cis-acting element refers to a specific DNA sequence with a stool-like transcriptional regulation function in the same DNA molecule. The cis-acting elements of eukaryotic genes can be divided into promoters, enhancers, silencers, and insulators according to their functions.

A promoter is a DNA-specific sequence that RNA polymerase recognizes and binds to. The RNA polymerase of eukaryotic cells recognizes not the DNA sequence alone, but the protein-DNA complex formed by the transcription factor with the DNA.

Enhancers refer to DNA sequences that can enhance the transcriptional activity of promoters, which can significantly enhance the transcriptional efficiency of promoters. Enhancers are regulatory sequences that enhance the transcriptional activity of genes by binding to specific transcription factors or by altering the structure of chromatin DNA.

Some sequences play a negative role in the regulation of transcription, that is, when a specific transcription factor binds to it, it acts as a repressor on transcription, and this cis-acting element is called silencer.

Insulators are a very special class of cis-acting elements, which differ from enhancers and silencers in that their function is only to prevent activation or inhibit the transmission of action on chromatin, thus limiting chromatin activity to the domain.

2) Trans-acting factors are proteins that recognize and bind cis-acting elements and regulate gene transcription, and the genes encoding trans-acting factors are located on different chromosomes or different DNA molecules with the target genes regulated by trans-acting factors. Different trans factors can be related to DNAInteraction of specific cis-acting elements and regulation of transcription is exerted through the interaction between nucleic acid proteins, protein proteins, and other molecules. Xiaohui.