Author Archives: gene_x

Workflow and Tools for Integrating ChIP-seq and RNA-seq Data Analysis

Here is a concise summary of the key steps and tools for ChIP-seq and RNA-seq data analysis and integration:

  1. Quality control: FastQC for assessing raw sequencing data quality.

  2. Trimming and filtering: Trimmomatic or Cutadapt for preprocessing reads.

  3. Alignment: Bowtie2 or BWA for ChIP-seq, and STAR, HISAT2, or TopHat2 for RNA-seq.

  4. Peak calling (ChIP-seq): MACS2, SICER, HOMER (see separate article) or diffReps.pl (part of the DiffReps package) for identifying bound genomic regions.

  5. Gene expression quantification (RNA-seq): featureCounts, HTSeq, or Cufflinks for expression levels.

  6. Differential expression analysis (RNA-seq): DESeq2 or edgeR for comparing conditions or time points.

  7. Motif analysis (ChIP-seq): MEME-ChIP for identifying enriched sequence motifs.

  8. Data visualization: deepTools or Integrative Genomics Viewer (IGV) for viewing aligned reads and peaks.

  9. Annotation and integration: ChIPseeker or HOMER for peak annotation, and GenomicRanges, DiffBind, or other R packages for integrating ChIP-seq and RNA-seq data.

  10. Functional enrichment analysis: GSEA, clusterProfiler, or DAVID for pathway and functional category enrichment.

  11. Visualization: ggplot2 or ComplexHeatmap for combined ChIP-seq and RNA-seq data.

Creating a Bubble Plot with ggplot2 and readxl in R

TFEB-wt24

The input file can be downloaded here!

The code for creating the bubble plot above is written in R and utilizes the ggplot2 and readxl packages. It has the following steps:

  1. Load required libraries: The ggplot2 library is used for data visualization, and the readxl library is used to read data from Excel files.

    library(ggplot2)
    library(readxl)
  2. Read the data: The read_excel() function reads the data from the “WT.xlsx” file and stores it in the WT dataframe.

    WT <- read_excel("WT.xlsx")
  3. Create the plot: The ggplot() function initializes the plot with the dataset (WT) and the aesthetics (Fold_Enrichment on the x-axis, reordered Term on the y-axis based on Log10FDR values).

    p = ggplot(WT, aes(Fold_Enrichment, reorder(Term, Log10FDR, order = TRUE)))
  4. Add color and size to points: This step adds color to the points based on the “Log10FDR” variable and sets the size according to the “Count” variable.

    pbubble = p + geom_point(aes(size=Count, color=Log10FDR))
  5. Customize the plot: This step sets the color gradient for points, labels the x-axis, and adjusts the size of the points.

    pr = pbubble + scale_color_gradient(low = "lightblue", high = "darkblue") +
      labs(x="Fold Enrichment", y="Term") +
      scale_size_continuous(range = c(1,10))
  6. Increase font size of y-axis labels: The theme() function is used to increase the font size of y-axis labels (terms) to 12.

    pr = pr + theme_bw() + theme(axis.text.y = element_text(size = 12))
  7. Save the plot: The png() function saves the plot as a PNG file with the specified dimensions, and the print() function prints the plot to the output file. The dev.off() function closes the graphics device, finalizing the output file.

    png("TFEB-wt24.png", width=700, height=500)
    print(pr)
    dev.off()

This code will generate a scatter plot with points colored and sized based on the “Log10FDR” and “Count” variables, respectively. The y-axis labels (terms) will be ordered according to the “Log10FDR” values and have an increased font size.

Population-Specific Genetic Variations

Genetic variations occur in the form of single nucleotide polymorphisms (SNPs), insertions and deletions (indels), and other structural variations in the DNA. Some of these genetic variations are more common in certain populations due to factors such as ancestry, migration, and natural selection. It’s essential to note that the vast majority of genetic variation is shared among all human populations, and the differences between populations are relatively small.

Here are some examples of genetic variations that have been observed among Asian, European, and African populations:

  1. Lactose tolerance: Lactase persistence, the ability to digest lactose in adulthood, is more common in people of European descent (around 80% prevalence) compared to Asian (20% prevalence) and African (varying prevalence depending on the population) populations. This is primarily due to the prevalence of the -13910*T allele near the lactase gene (LCT) in Europeans.

  2. Skin pigmentation: Skin color is influenced by the amount and type of melanin produced by melanocytes. Several genes are involved in determining skin color, with variations in these genes contributing to the differences in skin pigmentation among populations. For example, the SLC24A5 gene has a genetic variant (rs1426654) that is associated with lighter skin pigmentation and is more common in European populations compared to African and Asian populations.

  3. Blood group antigens: The ABO blood group system is determined by variations in the ABO gene. The distribution of ABO blood groups varies among populations. For instance, the B blood group is more common in Asian populations compared to European and African populations, while the O blood group is more prevalent in African populations.

  4. Genetic risk factors for diseases: Certain genetic variants are associated with an increased risk of developing specific diseases, and the prevalence of these variants can vary among populations. For example, the Apolipoprotein E (APOE) ε4 allele is associated with an increased risk of Alzheimer’s disease and is more common in European populations compared to Asian and African populations. Similarly, the frequency of genetic variants associated with Type 2 diabetes and obesity can also differ among populations.

It’s important to remember that genetic variations among populations are complex and influenced by many factors. Additionally, these variations represent only a small part of the overall genetic diversity within and among human populations. Genetic research is ongoing, and more detailed information about the genetic differences among populations continues to emerge as new data and technologies become available.

Global Prostate Cancer Prevalence and Genetic Variants

Prostate cancer prevalence varies among countries, with some regions having higher rates than others. According to the International Agency for Research on Cancer (IARC) and the World Cancer Research Fund International, here is a general overview of prostate cancer prevalence worldwide:

  1. High prevalence: Prostate cancer is most prevalent in developed countries, particularly in North America, Western and Northern Europe, and Australia. For example, the United States, Canada, Sweden, Norway, and the United Kingdom have some of the highest age-standardized incidence rates of prostate cancer globally.

  2. Moderate prevalence: Some regions have moderate rates of prostate cancer, including Eastern and Southern Europe, Central and South America, and parts of Asia, such as Japan and South Korea. In these regions, the prevalence of prostate cancer is lower than in high-prevalence countries but still relatively high compared to the global average.

  3. Low prevalence: Prostate cancer has a lower prevalence in many developing countries, particularly in Africa and Asia. For example, countries like Nigeria, India, and China have relatively low age-standardized incidence rates of prostate cancer.

Prostate cancer incidence and mortality rates differ among various racial and ethnic groups, and these differences may be partly due to genetic variations. Here are some genetic variants associated with prostate cancer that have been found to differ among Asian, Black, and White populations:

  1. 8q24 locus: This chromosomal region has been linked to prostate cancer risk, and several single nucleotide polymorphisms (SNPs) in this region have been associated with the disease. The risk associated with these SNPs varies among different populations, with a higher risk observed in individuals of African descent compared to those of European and Asian ancestry.

  2. 17q12 locus: The HNF1B gene located at the 17q12 locus has been found to have a strong association with prostate cancer risk. Studies have shown that the risk alleles at this locus are more common in individuals of European and Asian descent than in those of African descent.

  3. 17q24 locus: The 17q24 locus contains the SOX9 gene, which plays a role in prostate development. Genetic variants in this region have been associated with prostate cancer risk, and their frequency varies among different populations. The risk alleles are more common in individuals of European descent compared to Asian and African populations.

  4. 10q11 locus: The 10q11 locus contains the MSMB gene, which is involved in prostate function. Genetic variants in this region have been associated with prostate cancer risk, and their frequency differs among various populations. The risk alleles are more common in individuals of European descent than in those of Asian or African descent.

These differences in genetic variants among racial and ethnic groups might partly explain the observed differences in prostate cancer incidence and outcomes. However, it is important to note that environmental factors, lifestyle, and access to healthcare also contribute to these differences. Further research is needed to fully understand the complex interplay of genetics, environment, and other factors in prostate cancer risk and outcomes.

高通量测序技术与基因组学研究方法

  1. RNA-seq:RNA测序,一种高通量测序技术,用于研究转录组,了解基因的表达水平和结构。

  2. miRNA-seq:miRNA测序,针对小分子microRNA(miRNA)的高通量测序技术,用于研究miRNA在调控基因表达中的作用。

  3. ncRNA-seq:非编码RNA测序,研究非编码RNA(ncRNA)的高通量测序技术,这些RNA不编码蛋白质但在基因调控和细胞功能中发挥重要作用。

  4. RNA-seq (CAGE):带有毛细管分析基因表达(CAGE)的RNA测序,一种定量测量基因起始位点和表达水平的方法。

  5. RNA-seq (RACE):带有快速扩增cDNA末端(RACE)的RNA测序,用于确定转录本的5’和3’末端。

  6. ssRNA-seq:单链RNA测序,一种特殊的RNA测序技术,用于研究单链RNA的结构和功能。

  7. ChIP-seq:染色质免疫沉淀测序,结合染色质免疫沉淀和高通量测序技术,用于研究蛋白质和DNA之间的相互作用。

  8. MNase-seq:微coccal核酸酶测序,利用核酸酶对染色质进行切割并进行高通量测序,用于研究染色质结构和核小体定位。

  9. MBD-seq:甲基CpG结合蛋白测序,通过捕获甲基化CpG位点来研究DNA甲基化模式。

  10. MRE-seq:甲基化敏感限制酶测序,利用甲基化敏感的限制性内切酶分析DNA甲基化水平。

  11. Bisulfite-seq:硫酸氢盐测序,用于检测DNA中的甲基化位点。

  12. Bisulfite-seq (reduced representation):简化表示硫酸氢盐测序,是一种降低成本和复杂性的硫酸氢盐测序方法。

  13. MeDIP-seq:甲基化DNA免疫沉淀测序,通过免疫沉淀来捕获甲基化DNA片段,用于研究全基因组甲基化模式。

  14. DNase-Hypersensitivity:DNase I超敏感位点分析,用于检测与转录因子结合和开放染色质区域相关的DNA位点。

  15. Tn-seq:转座子测序,一种用于研究基因功能和表达调控的技术,通过分析转座子插入的位置来了解基因的重要性。

  16. FAIRE-seq:甲醛辅助同位素沉淀测序,用于研究开放染色质区域,这些区域通常与基因调控元件有关。

  17. SELEX:系统进化逐渐丢失的相关性,一种用于筛选具有高亲和力的核酸序列的技术,常用于研究RNA结构和功能。

  18. RIP-seq:RNA免疫沉淀测序,结合RNA免疫沉淀和高通量测序技术,用于研究RNA与蛋白质之间的相互作用。 它是一种结合RNA免疫沉淀和高通量测序技术的方法,用于研究RNA与蛋白质之间的相互作用。这种技术对于揭示转录后调控机制以及RNA结合蛋白在基因表达和功能中的作用具有重要意义。

    RIP-seq实验的基本步骤如下:

    • 使用特异性抗体免疫沉淀目标RNA结合蛋白。
    • 沉淀后,提取与蛋白质结合的RNA片段。
    • 对沉淀的RNA片段进行逆转录,生成cDNA文库。
    • 对cDNA文库进行高通量测序。
    • 分析测序数据,识别与目标蛋白质结合的RNA片段。

    通过RIP-seq实验,研究人员可以了解RNA结合蛋白与哪些RNA序列发生相互作用,从而揭示蛋白质在RNA加工、转运、翻译和降解等过程中的功能。

    inteRNA是一个由欧洲联盟资助的研究项目,旨在研究非编码RNA(ncRNA)在生物体中的功能及其在疾病发生中的作用。Björn Voss教授是这个项目的一个参与者。这个项目的目标是通过高通量测序技术和生物信息学方法研究非编码RNA的生物学功能,以便更好地了解它们在细胞发育和疾病过程中的作用。这些研究成果有望为未来的诊断和治疗方法提供新的见解。

  19. ATAC-seq:活动染色质转座子测序,一种测定开放染色质区域的技术,用于研究基因调控和表达。

  20. ChIA-PET:染色质相互作用分析-蛋白质共沉淀测序,结合染色质免疫沉淀和染色质共沉淀技术,用于研究远程染色质相互作用和基因调控。

  21. Hi-C:一种用于研究染色质三维结构和相互作用的技术,通过高通量测序和计算分析来揭示染色质在细胞核中的空间组织。

A Timeline of the Development of Microarray and NGS Technologies

A timeline of the history of microarray and next-generation sequencing technologies:

  • Microarray Technology:

    • 1990s: The first microarrays were developed, which used small glass slides or nylon membranes to spot DNA or RNA probes.
    • 2000s: Microarray technology became widely used in genomics research for measuring gene expression levels, identifying single-nucleotide polymorphisms (SNPs), and detecting copy number variations (CNVs).
    • 2008: The first whole-genome microarray was developed, allowing researchers to measure the expression levels of all known genes in a given organism.
    • 2010s: With the emergence of next-generation sequencing technology, the use of microarrays declined somewhat, but they continue to be used for specific applications, such as validating gene expression levels or detecting chromosomal abnormalities.
  • Next-Generation Sequencing (NGS) Technology:

    • 2005: The first next-generation sequencing technology, 454 pyrosequencing, was introduced, allowing researchers to sequence DNA fragments up to several hundred base pairs long.
    • 2007: The Illumina/Solexa platform was introduced, which allowed for high-throughput sequencing of millions of short DNA fragments in parallel.
    • 2008: The SOLiD platform was introduced, which uses a different sequencing chemistry than Illumina and can detect certain types of genetic variations more accurately.
    • 2010s: NGS technology continued to evolve, with improvements in read length, accuracy, and cost-effectiveness. Applications of NGS technology expanded to include whole-genome sequencing, transcriptome sequencing, epigenetic analysis, metagenomics, and more.
    • 2014: The Oxford Nanopore MinION device was introduced, which uses a novel nanopore sequencing technology and can sequence long DNA or RNA molecules in real-time.
    • 2020s: NGS technology remains a critical tool in genomics research and is being used to advance precision medicine, drug discovery, and other areas of biomedical research.

Overall, microarray and NGS technologies have transformed the field of genomics and have allowed researchers to answer questions about the molecular basis of disease and other biological processes. While each technology has its own strengths and limitations, they continue to be complementary tools for genomic analysis.

多瘤病毒科家族中的MCPyV与TSPyV

MCPyV(梅克尔细胞多瘤病毒,Merkel cell polyomavirus)和TSPyV(纺锤状毛发发育不良相关多瘤病毒,Trichodysplasia spinulosa-associated polyomavirus)都是多瘤病毒科(Polyomaviridae)家族的成员,这是一类可以感染各种脊椎动物的小型双链DNA病毒。尽管它们都属于同一家族,但它们与不同类型的疾病相关。

MCPyV与一种罕见的皮肤癌——梅克尔细胞癌(Merkel cell carcinoma,MCC)有关。梅克尔细胞癌是一种快速生长的神经内分泌肿瘤,主要发生在皮肤表面。MCPyV在大约80%的梅克尔细胞癌患者中被发现。MCPyV感染通常是无害的,但在某些情况下,病毒可能会整合到宿主细胞的基因组中,导致细胞恶性转化和肿瘤发展。

与之相反,TSPyV与一种罕见的皮肤病——纺锤状毛发发育不良(Trichodysplasia spinulosa,简称TS)相关。这种病状的特点是毛囊纺锤状突起、脱发和毛囊异常生长,主要影响免疫受损的个体,如器官移植受者或艾滋病患者。

尽管MCPyV和TSPyV都属于多瘤病毒科家族,它们在致病机制、相关疾病和受影响人群方面存在显著差异。研究这些病毒将有助于更好地了解它们的感染和致病机制,以及为相关疾病的患者开发有效的治疗策略。

Guide to Submitting Data to GEO (Gene Expression Omnibus)

  1. Create an account: First, create a GEO account at https://www.ncbi.nlm.nih.gov/geo/submission/. If you already have an NCBI account, you can use the same credentials to log in.

  2. Upload data files via FTP: Upload your raw data and processed data files to the GEO server using an FTP client. Please refer to GEO’s FTP upload instructions: https://www.ncbi.nlm.nih.gov/geo/info/ftp.html.

  3. Download the appropriate template: Based on your data type, download the corresponding Excel template (called “SOFT” files) from the GEO submission guidelines page: https://www.ncbi.nlm.nih.gov/geo/info/seq.html. There are different templates for platforms, samples, and series.

  4. Prepare metadata in the Excel template: Fill out the Excel template with the required information about your samples, platform, and series (experiment). Be sure to follow the GEO guidelines for formatting and required fields.

    • Platform: Describe the technology used for data generation (e.g., microarray or RNA-seq). Provide platform details like manufacturer, layout, probe sequences, etc.

    • Samples: Provide sample details such as source, treatment, extraction protocol, labeling, and hybridization methods. Also, include any relevant clinical or phenotypic data.

    • Series: Describe the overall experiment design and goals, as well as any related publications or supplementary files.

  5. Submit the Excel template: Log in to the GEO Submission Portal (https://www.ncbi.nlm.nih.gov/geo/submission/) using your NCBI account. Click “Submit” to start a new submission and upload the completed Excel template.

    Download an Excel template

    Download an example Excel file for ChIP-seq submission

    Download an example Excel file for RNA-seq submission

  6. Notify GEO about your FTP file transfer (suitable for high-throughput sequencing or large microarray submissions and updates). GEO_notify_screenshot

  7. Wait for the review: The GEO team will review your submission and may contact you for additional information or clarification. Once your submission is approved, you will receive a confirmation email containing your GEO accession number(s).

  8. Cite your data: Include the GEO accession number(s) in any related publications or presentations to ensure proper attribution and facilitate data discovery.

For more detailed instructions and guidelines, visit the GEO Submission Guidelines page: https://www.ncbi.nlm.nih.gov/geo/info/submission.html.

Quick Instructions

  1. Check that GEO accepts your data type.
  2. Gather raw data files.
  3. Gather processed data files .
  4. Fill in Metadata Template (one seq type per template). Please review “Before completing your Metadata Template” below.
  5. Fill in MD5 Checksums sheet for any raw data files and processed data files referenced in Metadata Template.
  6. Create a folder on your computer that contains all raw and processed files and your completed Metadata Template in Excel format.
  7. FTP the entire data folder to GEO.
  8. Notify GEO using the ‘Submit to GEO’ web form, after the FTP transfer is complete; unannounced files will not be processed.
  9. Your submission is placed into the processing queue and reviewed within 5 business days; expect to receive an email from GEO curators with questions about your submission or the GEO accession numbers.

* Updating GEO records (that have been processed and approved) can be labor-intensive and time-consuming, so please carefully prepare your submission before you transfer your files to the GEO FTP server.

* A complete GEO submission consists of the following 3 components. If your transfer does not include all 3 components, please explain the reason in the comment box below. An incomplete submission may result in processing delays.

  • Completed metadata worksheet
  • Raw data
  • Processed data

* When this submission should be released to the public (more information about release dates)

  • Keep my existing release date
  • Specify a new future release date for the submission being updated (up to 4 years from today). New release dates apply only to submissions that are still private.

https://submit.ncbi.nlm.nih.gov/geo/submission/

https://www.ncbi.nlm.nih.gov/geo/info/faq.html#holduntilpublished

https://www.ncbi.nlm.nih.gov/geo/submitter/

https://www.ncbi.nlm.nih.gov/geo/subs/

耶尔森氏菌Type III分泌系统效应蛋白

  1. type III secretion system translocon subunit YopB:YopB (Yersinia outer protein B) 是Yersinia属细菌的一种效应蛋白,与YopD共同参与形成跨膜通道,使其他Yop效应蛋白能够穿过宿主细胞膜进入宿主细胞。

  2. type III secretion system translocon subunit YopD:YopD (Yersinia outer protein D) 与YopB共同作用,形成一种跨膜通道,有助于其他Yop效应蛋白进入宿主细胞。此外,YopD还参与调控Type III分泌系统(T3SS)的效应蛋白的分泌。

  3. type III secretion system effector YopK:YopK 是一种调控蛋白,主要作用是细调Type III分泌系统的效应蛋白进入宿主细胞的程度,从而平衡细菌的毒力和免疫逃避。

  4. T3SS effector protein-tyrosine-phosphatase YopH:YopH 是一种酪氨酸磷酸酶,可以抑制宿主细胞的信号传导,从而干扰细胞粘附和免疫细胞的功能,有助于细菌逃避宿主的免疫系统。

  5. type III secretion system effector acetyltransferase YopJ:YopJ 是一种酰基酶,可以抑制宿主细胞内的NF-κB和MAPK信号通路,进而抑制炎症反应和细胞凋亡,有助于细菌逃避宿主免疫系统。

  6. SctW family type III secretion system gatekeeper subunit YopN:YopN 主要作为Type III分泌系统的分泌调控蛋白,可防止Yop效应蛋白在细菌内过早分泌,以确保在适当时机释放。

  7. type III secretion system effector YopM:YopM 是一种调节蛋白,可以促进炎性细胞凋亡,抑制细胞因子的产生,从而降低宿主的炎症反应。

  8. T3SS polymerization control protein YopR:关于YopR的信息有限,可能是一个错误的命名,与YopM和YopN重复。

  9. type III secretion system effector GTPase activator YopE:YopE 是一种GTP酶激活蛋白(GAP),通过抑制宿主细胞的Rho GTP酶家族成员来破坏细胞骨架,从而削弱宿主细胞的免疫反应。

  10. type III secretion system effector protein kinase YopO/YpkA:YopO(又称YpkA)是一种丝氨酸/苏氨酸蛋白激酶,可以通过干扰宿主细胞的细胞骨架,抑制细胞迁移,从而影响免疫细胞的功能。此外,YopO还可以激活Rho GTP酶家族成员,影响宿主细胞的信号传导。

  11. T3SS effector cysteine protease YopT:YopT 是一种具有蛋白酶活性的效应蛋白,主要通过切割宿主细胞的Rho GTP酶家族成员,破坏宿主细胞的细胞骨架,从而干扰细胞粘附和迁移。

这11种Yersinia属细菌的Type III分泌系统效应蛋白在病原体侵染过程中具有重要作用。它们通过破坏宿主细胞的信号传导和细胞骨架、抑制炎症反应和细胞凋亡等方式,协同作用以维持病原体在宿主体内的生存和繁殖。了解这些效应蛋白的功能和作用机制对于研究Yersinia属细菌的致病机制和寻找新的治疗方法具有重要意义。

How to run AlphaFold2?

AlphaFold2 is a protein structure prediction model developed by DeepMind. To run AlphaFold2, you’ll need to follow these steps:

  1. Clone the AlphaFold repository:

    git clone https://github.com/deepmind/alphafold.git
    cd alphafold
  2. Set up the environment:

    You will need to install the necessary dependencies for AlphaFold. It’s recommended to use a Python virtual environment or a Conda environment.

    If you’re using a Python virtual environment, create and activate it:

    python3 -m venv alphafold_venv
    source alphafold_venv/bin/activate

    Then install the required packages:

    pip install -r requirements.txt

    If you prefer to use Conda, create a Conda environment and activate it:

    conda create -n alphafold python=3.8
    conda activate alphafold

    Then install the required packages:

    conda install -c conda-forge openmm
    conda install -c conda-forge pdbfixer
    pip install -r requirements.txt
  3. Download the necessary model data:

    You need to download the model parameters and databases. Create a directory to store the data:

    mkdir data

    Download the model parameters from the AlphaFold GitHub repository:

    wget -P data/ https://storage.googleapis.com/alphafold/alphafold_params_2021-07-14.tar
    tar -xf data/alphafold_params_2021-07-14.tar -C data/

    Download the necessary databases (e.g., UniRef, BFD, and MGnify). You can find instructions on how to download them in the README.md file in the AlphaFold repository or on their respective websites.

  4. Run AlphaFold2:

    You can run the AlphaFold2 using the provided run_alphafold.py script. For example, to predict the structure of a protein with the sequence in input.fasta, you can use the following command:

    python run_alphafold.py --fasta_paths=input.fasta --output_dir=output/ --preset=full_dbs --max_template_date=2099-12-31 --data_dir=data/

    This command will run the full AlphaFold2 pipeline with all available databases and store the resulting structures in the output/ directory.

    Make sure to replace input.fasta with the path to your input FASTA file, and adjust other options as needed.

  5. Analyze the results:

    After the prediction is finished, you can find the predicted structures in the output/ directory. The PDB files can be visualized using molecular visualization software such as PyMOL, Chimera, or VMD.