Chicken slc11a1 gene core promoter and construction method and application thereof

Abstract

The present application relates to the field of molecular biology and genetic engineering technology, and discloses a chicken SLC11A1 gene core promoter and a construction method and application thereof.The sequence of the chicken SLC11A1 gene core promoter is shown in SEQ ID NO:2, and the chicken SLC11A1 gene core promoter has significant promoter activity in a chicken monocyte macrophage cell line HD11.The present application simultaneously discloses a construction method for specifically amplifying the core promoter, and the construction method comprises the following steps: taking a chicken SLC11A1 full-length promoter fragment (SEQ ID NO:1) as a template to perform PCR amplification, and the upper and lower upstream primers are shown in SEQ ID NO:15 and 23 respectively, and a core promoter fragment is obtained by amplification.The core promoter provides an excellent experimental system for studying the transcriptional regulation mechanism of the chicken SLC11A1 gene.

Description

Technical Field

[0001] This invention relates to the fields of molecular biology and genetic engineering, and more specifically, to the chicken SLC11A1 gene core promoter, its construction method, and its application. Background Technology

[0002] The SLC11A1 gene (member 1 of the solute vector family 11), also known as the NRAMP1 gene, encodes a protein that plays a crucial role in the body's innate immune response, regulating the ability of macrophages to clear intracellular pathogens (such as Salmonella and Mycobacterium tuberculosis). In the chicken farming industry, Salmonella infection is a common bacterial disease, not only leading to increased morbidity and mortality in chicken flocks but also posing a threat to human health through the food chain. Therefore, in-depth research into the expression regulation mechanism of the chicken SLC11A1 gene is of great significance for breeding disease-resistant chicken breeds and ensuring the healthy development of the poultry industry.

[0003] As a core element in gene expression regulation, the promoter recruits RNA polymerase and transcription factors, determining the transcription initiation time and expression intensity of a gene. Promoters are specific to different species and different genes, and their core regions directly affect the tissue specificity and inducible expression characteristics of the gene. Currently, research on the identification of the chicken SLC11A1 gene promoter is lacking. Existing technologies lack precise identification methods for this gene promoter and have not clarified its core functional regions. This greatly limits in-depth analysis of the chicken SLC11A1 gene expression regulation mechanism and the development of disease-resistant breeding technologies based on this gene.

[0004] Therefore, cloning and identifying the core promoter of the chicken SLC11A1 gene has become a pressing technical challenge in this field. This has significant theoretical and practical implications for advancing disease-resistant breeding in chickens. Summary of the Invention

[0005] The purpose of this invention is to provide the chicken SLC11A1 gene core promoter, its construction method, and its application.

[0006] To achieve the objective of this invention, in a first aspect, this invention provides a chicken SLC11A1 gene core promoter, the nucleotide sequence of which is as follows: i) The nucleotide sequence shown in SEQ ID NO:2; or, ii) A nucleotide sequence showing the nucleotide sequence of SEQ ID NO:2 that has been substituted, deleted, and / or had one or more nucleotides added, and has the same function; or, iii) A nucleotide sequence that hybridizes with the sequence shown in SEQ ID NO:2 under stringent conditions, wherein the stringent conditions are hybridization at 65°C in 0.1×SSPE containing 0.1% SDS or 0.1×SSC containing 0.1% SDS, followed by washing the membrane with the same solution; or, iv) Nucleotide sequences that are more than 90% homologous to and have the same function as nucleotide sequences of i), ii) or iii).

[0007] In this invention, the gene ID of the chicken SLC11A1 gene in NCBI is 395811.

[0008] Secondly, the present invention provides a primer pair for amplifying the core promoter of the chicken SLC11A1 gene, the primer pair comprising: an upstream primer with a nucleotide sequence as shown in SEQ ID NO:15 and a downstream primer with a nucleotide sequence as shown in SEQ ID NO:23.

[0009] Thirdly, the present invention provides a method for constructing the core promoter of the chicken SLC11A1 gene, comprising the following steps: (1) Genomic DNA was extracted from chicken cecal tissue; (2) Using the genomic DNA extracted in step (1) as a template, PCR amplification was performed using the upstream primer shown in SEQ ID NO:3 and the downstream primer shown in SEQ ID NO:9 to obtain the full-length promoter fragment of the SLC11A1 gene shown in SEQ ID NO:1; (3) Using the full-length SLC11A1 promoter fragment obtained in step (2) as a template, PCR amplification was performed using the primer pair (SEQ ID NO: 15 and 23) to obtain the chicken SLC11A1 gene core promoter.

[0010] Fourthly, the present invention provides an expression cassette containing the core promoter of the chicken SLC11A1 gene.

[0011] Fifthly, the present invention provides a recombinant vector or recombinant plasmid containing the chicken SLC11A1 gene core promoter or the expression cassette.

[0012] Preferably, the starting vector for the recombinant plasmid is pGL3-Basic.

[0013] In a sixth aspect, the present invention provides engineered bacteria or transgenic cell lines (preferably the chicken mononuclear macrophage cell line HD11) containing the chicken SLC11A1 gene core promoter or the expression cassette or the recombinant vector or recombinant plasmid.

[0014] In a seventh aspect, the present invention provides the application of the chicken SLC11A1 gene core promoter in regulating the expression of downstream genes.

[0015] Eighthly, the present invention provides any of the following applications of the chicken SLC11A1 gene core promoter, the expression cassette, the recombinant vector, the recombinant plasmid, the engineered bacteria, or the transgenic cell line: 1) Used for research on the regulatory mechanism of chicken SLC11A1 gene expression; 2) Used for research on the immune mechanisms of chicken infections; 3) Used to construct a reporter gene system for expressing firefly luciferase in the chicken mononuclear macrophage cell line HD11.

[0016] By employing the above technical solution, the present invention has at least the following advantages and beneficial effects: (i) This invention establishes for the first time a specific identification method for the chicken SLC11A1 gene promoter, filling the gap in existing research on the chicken SLC11A1 gene expression regulation mechanism. This method employs a four-round truncation localization strategy, integrating molecular cloning and dual-luciferase reporter system technology, which can accurately locate the core promoter region, and the identification results are reliable and highly reproducible.

[0017] (ii) This invention clarifies the specific sequence (-172bp~+19bp) of the core promoter of the chicken SLC11A1 gene. This core region has strong promoter activity and is the core element for regulating the precise expression of the chicken SLC11A1 gene.

[0018] (III) The core promoter identified in this invention can serve as a new target for disease-resistant breeding of chickens. By constructing an expression vector containing this promoter, the specific expression of disease-resistant genes in chicken immune tissues can be achieved, significantly enhancing the resistance of chicken flocks to intracellular pathogens and reducing the occurrence of diseases during the breeding process. It has important industrial application value.

[0019] (iv) The identification method of the present invention is simple and efficient to operate. The required reagents and instruments are all conventional molecular biology experimental supplies, which are easy to promote and apply. It can provide a reference paradigm for the identification of other poultry gene promoters.

[0020] (v) This invention not only elucidates the key molecular basis of chicken SLC11A1 gene expression regulation in theory, but also provides a practical tool for immune research in application, which has both scientific value and industrial potential. Attached Figure Description

[0021] Figure 1 This is a graph showing the luciferase activity detection results of the first round of preliminary truncated recombinant plasmid of the chicken SLC11A1 gene in a preferred embodiment of the present invention.

[0022] Figure 2 This is a graph showing the luciferase activity detection results of the second round of finely truncated recombinant plasmid of the chicken SLC11A1 gene in a preferred embodiment of the present invention.

[0023] Figure 3 This is a graph showing the luciferase activity detection results of the third round of finely truncated recombinant plasmid of the chicken SLC11A1 gene in a preferred embodiment of the present invention.

[0024] Figure 4 This is a graph showing the luciferase activity detection results of the fourth round of finely truncated recombinant plasmid of the chicken SLC11A1 gene in a preferred embodiment of the present invention.

[0025] In the figure, each bar represents a recombinant plasmid with a truncated promoter. The unit of recombinant plasmid is bp. Different lowercase letters between the two groups indicate statistically significant differences (P < 0.05). Detailed Implementation

[0026] This invention provides a chicken SLC11A1 gene core promoter, its identification, construction method, and application, which solves the technical problems of unclear chicken SLC11A1 gene core promoter and lack of accurate identification methods in the prior art. It can be applied to fields such as genetic engineering and breeding engineering for chicken genetic improvement.

[0027] The present invention adopts the following technical solution: The present invention provides a chicken SLC11A1 gene core promoter, the sequence of which is shown in SEQ ID NO:2.

[0028] The present invention also provides a primer pair for amplifying the core promoter of the chicken SLC11A1 gene, the primer pair comprising: an upstream primer as shown in SEQ ID NO:15 and a downstream primer as shown in SEQ ID NO:23.

[0029] The present invention also provides a method for constructing the core promoter of the chicken SLC11A1 gene, comprising the following steps: firstly, using DNA extracted from chicken cecal tissue as a template, a full-length promoter fragment of SLC11A1 (SEQ ID NO:1) is obtained by PCR amplification; then, using the full-length promoter fragment of SLC11A1 as a template, PCR amplification is performed using the primers (SEQ ID NO:15 and 23) as described above to obtain the core promoter of the chicken SLC11A1 gene.

[0030] The present invention also provides a recombinant plasmid comprising the chicken SLC11A1 gene core promoter.

[0031] The present invention also provides the application of the chicken SLC11A1 gene core promoter or the expression vector containing the chicken SLC11A1 gene core promoter in chicken genetic improvement.

[0032] The present invention also provides applications of the chicken SLC11A1 gene core promoter, including at least the following aspects: (1) application to initiate the expression of firefly luciferase in eukaryotic cells, wherein the eukaryotic cells are chicken mononuclear macrophage cell line HD11; (2) application in an experimental system for studying the transcriptional regulation mechanism of the chicken SLC11A1 gene; and (3) application in the study of chicken infection immune mechanisms.

[0033] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.

[0034] Example 1: Predicting cis-acting elements in the promoter region of the chicken SLC11A1 gene 1. Log in to the NCBI database (https: / / www.ncbi.nlm.nih.gov / ), search for the chicken (Gallus gallus) SLC11A1 gene, whose gene ID is 395811, and download the sequence from 2090bp (-) upstream to 486bp (+) downstream of the transcription start site (TSS, +1 site). This is the full-length candidate promoter sequence, and the nucleotide sequence is shown in SEQ ID NO:1.

[0035] 2. Prediction using the TSSW online tool revealed that the promoter region of this gene contains a typical TATA-box cis-acting element, specifically located 31 bp to 28 bp upstream of the transcription start site.

[0036] Example 2: Construction of a recombinant reporter vector for the chicken SLC11A1 gene promoter 1. This study employed a four-round progressive design of promoter truncated primers to complete the initial screening and fine localization of the promoter core region. The first round involved large-scale preliminary truncation: specific amplification primers were developed for the full-length candidate promoter fragment (-2090bp~+486bp) and five initially truncated fragments (-1607bp~+486bp, -1176bp~+486bp, -672bp~+486bp, -206bp~+486bp, +234bp~+486bp). The second round involved fine truncation of the region: combining the results of the first round of dual-luciferase activity assays, the core candidate region was initially identified as - Within the range of 672bp to +233bp, multiple gradient-truncated fragments were designed, including -672bp to +233bp, -571bp to +233bp, -474bp to +233bp, -377bp to +233bp, -275bp to +233bp, -172bp to +233bp, -35bp to +233bp, +49bp to +233bp, and +138bp to +233bp, and corresponding specific primers were synthesized. The third round involved determining whether the -172bp to -36bp core promoter region identified in the second round possessed promoter activity independently, designing primers for truncated versions of -172bp to -36bp and -672bp to -173bp. The fourth round was used for functional validation of key cis-acting elements: specific primers were designed for fragments of -172bp to +19bp, -172bp to +79bp, -172bp to +131bp, and -172bp to +186bp to validate the synergistic transcriptional regulatory role of TATA-box elements in the -172bp to -36bp range. All upstream primers for truncated variants had an NheI restriction site (GCTAGC) and two protective bases (CG) added to the 5' end, while the downstream primers had a HindIII restriction site (AAGCTT) and three protective bases (CCC) added to the 5' end. The primer sequences are shown in Table 1, with the corresponding positions of each truncated variant also indicated in the table. Table 1. Primer sequences for promoter fragment amplification

[0037] Note: The number in parentheses after the primer sequence is the sequence number of that primer.

[0038] 2. PCR Amplification: Genomic DNA was extracted from chicken cecal tissue using the Tiangen Genomic DNA Extraction Kit, and the DNA purity was detected using a micro spectrophotometer (A260 / A280 = 1.8~2.0). Using the extracted genomic DNA as a template, the promoter fragments of the initial truncated mutants were amplified in the first round. The truncated mutants in the second, third, and fourth rounds were all amplified using the full-length promoter fragments from the first round as templates.

[0039] The PCR reaction system is shown in Table 2.

[0040] Table 2 PCR reaction system

[0041] The PCR amplification procedure is shown in Table 3: Table 3 PCR amplification program

[0042] 3. After amplification, the amplified PCR products are spotted onto a 1% agarose gel. After electrophoresis detection of the PCR products, the results are observed in the gel imaging system. The PCR products are recovered by gel cutting using the Tiangen Company's ordinary agarose gel DNA recovery kit. The specific operation steps are performed according to the kit's instructions.

[0043] 4. Double Enzyme Digestion: The recovered promoter fragments were double-digested with the pGL3-Basic vector (Promega, Beijing) using the restriction endonucleases NheI-HF and HindIII-HF, respectively. The digestion reaction system is shown in Table 4. The digestion system was incubated in a PCR instrument at 37°C for 12 hours. After verification by 1% agarose gel electrophoresis, the digested fragments were recovered.

[0044] Table 4 Enzyme digestion reaction system

[0045] 5. Ligation reaction: The enzyme-digested promoter fragment and the pGL3-Basic vector fragment were ligated using T4 DNA ligase from New England Biotechnology (Beijing) Co., Ltd. The ligation reaction system is shown in Table 5. The reaction system was placed in a PCR instrument and ligated overnight in a metal bath at 16°C.

[0046] Table 5 Connection Reaction System

[0047] 6. Transformation and Screening: The ligation product was transformed into *E. coli* DH5α competent cells, incubated on ice for 30 min, heat-shocked at 42℃ for 90 s, incubated on ice for 5 min, and then 1 ml of LB medium was added. The cells were incubated at 37℃ with shaking at 180 rpm for 1 h. 30 μL of the bacterial culture was spread onto LB solid medium containing ampicillin (100 μg / mL) and incubated upside down at 37℃ for 12–16 h. Single colonies were picked and inoculated into LB liquid medium containing ampicillin and incubated at 37℃ with shaking at 220 rpm for 1 h.

[0048] 7. Sequencing verification: The recombinant plasmid cultured by shaking was sent to BGI Genomics Co., Ltd. for Sanger sequencing. The sequencing results were compared with the expected promoter sequence to confirm that the fragment insertion was correct, the sequence had no mutations and the orientation was correct, and the recombinant reporter vector was successfully constructed. Subsequently, plasmid was extracted from the constructed recombinant reporter vector.

[0049] Example 3: Preliminary identification of the core candidate region of the chicken SLC11A1 gene promoter using a dual-luciferase reporter system. 1. Culture of chicken mononuclear macrophage line HD11 (1) Cell resuscitation: Take out the frozen cells from liquid nitrogen, immediately place them in a 37°C water bath and shake them. After the cell solution is completely dissolved, add the cell solution to 5 mL of complete culture medium and mix well. Centrifuge at 1200 rpm for 5 minutes, remove the supernatant, resuspend the cell pellet in 1 mL of complete culture medium and mix well. Add the pellet to a T25 cell culture flask, shake well, and incubate in a 37°C, 5% CO2 incubator. (2) Cell medium change: Observe cell density and morphology under a microscope. Generally, change the medium every 24 hours. Warm the cell culture medium in advance, discard the old culture medium, and add new culture medium. (3) Cell passage: Under a microscope, when the cell confluence reaches about 90%, passage is performed. The old culture medium is transferred to a 15 mL centrifuge tube, and 2 mL of 0.25% trypsin is added to T25. The cells are digested in a 37°C incubator for 1 min. Under a microscope, the cells are observed until they detach from the cell wall and form a single-cell suspension. 2 mL of the old culture medium is added to stop the digestion. The cell suspension is added to a 15 mL centrifuge tube, centrifuged at 1200 rpm for 5 min, the supernatant is discarded, and the cell pellet is fully resuspended with 1 mL of complete culture medium. The pellet is then added to a T25 containing 5 mL of culture medium, mixed well, and incubated in a 37°C, 5% CO2 incubator.

[0050] 2. Plasmid transfection Cell transfection was performed according to the TransIT-X2® Dynamic Delivery System reagent (Mirus, MIR6000) instructions: (1) Transfer the cells to 24-well plates for culture, with 3 replicate wells in each group, and set up pGL3-Basic control vector. Transfection was performed when the cell density was 70%. (2) Equilibrate the TransIT-X2 to room temperature and gently vortex it before use; (3) Add 50 μL of Opti-MEM® culture medium to the empty tube; (4) Add 487.5 ng of recombinant plasmid / control vector and 12.5 ng of pRL-TK plasmid, and mix gently and thoroughly; (5) Add 1.5 μL TransIT-X2, mix gently and thoroughly, and let stand at room temperature for 15-30 min; (6) Add the prepared transfection reagent evenly to the cultured cells and continue culturing in the incubator for 40 hours.

[0051] 3. Dual-luciferase reporter gene assay Dual-Luciferase reporter gene assay was performed according to the instructions for the Dual-Luciferase® Reporter Assay System (Promega, E1910): (1) Preparation of lysis buffer to lyse cells: Prepare lysis buffer by mixing 1 volume of 5×Passive Lysis Buffer with 4 volumes of distilled water. Remove the culture medium, add 100 μL of cell lysis buffer to the cell culture plate, lyse thoroughly for 15 min, and aspirate the supernatant for subsequent assays; (2) Preparation of Luciferase Assay Reagent II: Calculate the required detection buffer according to the volume of 100 µL for each sample, and resuspend the lyophilized Luciferase Assay Substrate (provided by the kit) in 10 mL of Luciferase Assay Buffer II provided by the kit to prepare Luciferase Assay Reagent II (LARII) working solution; (3) Preparation of Stop&Glo® reagent: Add 1 volume of 50X Stop&Glo® substrate to 50 volumes of Stop&Glo® buffer solution, mix well and set aside; (4) Determination of firefly luciferase: Add 20 µL of cell lysis buffer to the microplate, then add 100 µL of firefly luciferase detection reagent, mix well by pipetting, place in the microplate reader, and the value of chemiluminescence is the firefly luciferase value. (5) Determination of Renal luciferase: After the above steps are completed, add 100 µL of Renal luciferase detection buffer, mix well by pipetting, and place in an ELISA reader to determine the Renal luciferase value. (6) Calculate: The ratio of the luciferase value of firefly to that of kidney luciferase is the relative value of the promoter activity of the fluorescent carrier.

[0052] 4. Results The results of the first round of preliminary truncation activity testing are as follows: Figure 1As shown, compared with the control group pGL3-Basic, the -672bp~+486bp and -206bp~+486bp fragments exhibited significantly higher promoter activity, and were significantly higher than -2090bp~+486bp, -1607bp~+486bp, -1176bp~+486bp, and +234bp~+486bp, initially narrowing the candidate core region of the chicken SLC11A1 gene promoter to -672bp~+233bp; to accurately define the core promoter range, a second round of fine truncation and activity verification was conducted on the -672bp~+233bp region. Figure 2 The results showed that the -672bp~+233bp, -571bp~+233bp, -474bp~+233bp, -377bp~+233bp, -275bp~+233bp, and -172bp~+233bp regions all possessed highly efficient promoter transcriptional activity, and all of these active vectors contained a common fragment of -172~-36bp. Deletion of this common fragment resulted in complete loss of promoter transcriptional activity in the truncated versions of -35bp~+233bp, +49bp~+233bp, and +138bp~+233bp, suggesting that -172bp~-36bp is a key region for maintaining the basic activity of the SLC11A1 gene promoter. To verify the functional independence of this region, luciferase reporter vectors containing only the -172bp~-36bp fragment and those lacking the -672bp~-173bp fragment were constructed, and a third round of activity assays were performed. The results showed that the -672~-173bp fragment lacked promoter activity after the deletion of the -172~-36bp region; however, the -172~-36bp fragment alone could effectively drive high-level expression of the reporter gene, confirming that this region possesses independent transcriptional activation capabilities. Simultaneously, the promoter activity of the -172~+233bp fragment was significantly higher than that of the -172~-36bp fragment, indicating the existence of a positively regulating cis-acting element (CLE) within the -35bp~+233bp region. Figure 3 In summary, it can be determined that -172 to -36 bp is the essential core region for maintaining the basic activity of the chicken SLC11A1 gene promoter.

[0053] Example 4: Precise positioning of the core promoter and verification of the control function of the TATA-box element Combining the experimental conclusions of Example 3 with the bioinformatics prediction results of Example 1, a functional cis-acting element exists in the -35bp to +233bp region of the chicken SLC11A1 gene promoter, with a typical TATA-box core element present in the -31bp to -28bp region. Based on previous experimental results, the -172 to +233bp fragment covering both the -172 to -36bp region and the TATA-box element exhibits significantly higher promoter transcriptional activity than the fragment containing only the -172 to -36bp region, demonstrating a synergistic transcriptional regulatory effect between the upstream -172 to -36bp region and the TATA-box element. To further precisely define the boundaries of the SLC11A1 gene core promoter, this study constructed a series of finely truncated vectors at -172bp to +19bp, -172bp to +79bp, -172bp to +131bp, and -172bp to +186bp. Dual-luciferase assay results showed that the promoter activity of the -172bp to +19bp fragment was the highest, 8.6 times that of the basal core fragment of -172bp to -36bp. Further extension of the fragment to -172bp to +79bp, -172bp to +131bp, and -172bp to +186bp all resulted in varying degrees of decrease in promoter activity. Figure 4 Based on multiple rounds of truncation verification and element function analysis, the core promoter region of the chicken SLC11A1 gene was finally determined to be -172bp to +19bp. Among them, -172bp to -36bp is the essential region for maintaining the basic transcriptional activity of this gene. The TATA-box element located at -31bp to -28bp can synergistically work with the upstream core region to significantly enhance the transcription initiation efficiency. Together, they constitute the efficient and precise transcription initiation regulatory module of the SLC11A1 gene.

[0054] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. The chicken SLC11A1 gene core promoter, characterized in that, The nucleotide sequence of the chicken SLC11A1 gene core promoter is shown in SEQ ID NO:

2.

2. A primer pair for amplifying the core promoter of the chicken SLC11A1 gene as described in claim 1, characterized in that, The primer pair includes an upstream primer with a nucleotide sequence as shown in SEQ ID NO:15 and a downstream primer with a nucleotide sequence as shown in SEQ ID NO:

23.

3. A method for constructing the core promoter of the chicken SLC11A1 gene, characterized in that, Includes the following steps: (1) Genomic DNA was extracted from chicken cecal tissue; (2) Using the genomic DNA extracted in step (1) as a template, PCR amplification was performed using the upstream primer shown in SEQ ID NO:3 and the downstream primer shown in SEQ ID NO:9 to obtain the full-length promoter fragment of the SLC11A1 gene shown in SEQ ID NO:

1. (3) Using the full-length promoter fragment of the SLC11A gene obtained in step (2) as a template, PCR amplification is performed using the primer pair described in claim 2 to obtain the desired result.

4. An expression cassette containing the chicken SLC11A1 gene core promoter as described in claim 1.

5. A recombinant vector or recombinant plasmid containing the chicken SLC11A1 gene core promoter as described in claim 1 or the expression cassette as described in claim 4.

6. The recombinant vector or recombinant plasmid according to claim 5, characterized in that, The recombinant plasmid originated from pGL3-Basic.

7. Engineered bacteria containing the chicken SLC11A1 gene core promoter as described in claim 1, or the expression cassette as described in claim 4, or the recombinant vector or recombinant plasmid as described in claim 5 or 6.

8. A transgenic cell line containing the chicken SLC11A1 gene core promoter of claim 1, or the expression cassette of claim 4, or the recombinant vector or recombinant plasmid of claim 5 or 6.

9. The application of the chicken SLC11A1 gene core promoter as described in claim 1 in regulating the expression of downstream genes.

10. Any of the following applications of the chicken SLC11A1 gene core promoter of claim 1, the expression cassette of claim 4, the recombinant vector or recombinant plasmid of claim 5 or 6, the engineered bacteria of claim 7, or the transgenic cell line of claim 8: 1) Used for research on the regulatory mechanism of chicken SLC11A1 gene expression; 2) Used for research on the immune mechanisms of chicken infections; 3) Used to construct a reporter gene system for expressing firefly luciferase in the chicken mononuclear macrophage cell line HD11.

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