When a stem cell differentiates and changes in size and shape, specific genes are being...
1. expressed
2. senescence
3. splicing
4. totipotent, pluripotent, multipotent
5. chemicals in the body
expressed or activated. When a stem cell differentiates, it undergoes a process called gene expression, where specific genes are switched on or off. The activation of certain genes leads to the production of specific proteins, which ultimately determine the size, shape, and function of the differentiated cell. This gene expression is tightly regulated and controlled by various mechanisms within the cell.
To understand which specific genes are being expressed during stem cell differentiation, researchers typically employ techniques such as gene expression profiling or transcriptome analysis. Here's a basic overview of the steps involved in determining gene expression:
1. Isolation of RNA: Researchers extract RNA from the stem cells at different stages of differentiation. RNA represents the genetic material that is transcribed from DNA and serves as a template for protein synthesis.
2. Reverse transcription: The extracted RNA is converted into complementary DNA (cDNA) through a process called reverse transcription. This step is necessary as most gene expression analysis techniques work with DNA rather than RNA.
3. Amplification: The cDNA is then amplified using techniques like polymerase chain reaction (PCR). Amplification produces multiple copies of the specific DNA sequences present in the original RNA sample, allowing for more accurate analysis.
4. Microarray analysis: Researchers can use DNA microarrays, also known as gene chips, to examine the expression of thousands of genes simultaneously. These microarrays consist of tiny spots containing small DNA sequences that represent different genes. The cDNA from the stem cell samples is labeled with a fluorescent marker and applied to the microarray. The labeled cDNA will only bind to the spots on the microarray if the corresponding gene is expressed, allowing for gene expression profiling.
5. Next-generation sequencing: An alternative method to microarrays is next-generation sequencing, which can sequence the entire transcriptome of a sample. This technology allows for a more comprehensive analysis of gene expression by determining the sequence of all the RNA molecules present in the sample.
6. Data analysis: The final step involves analyzing the gene expression data obtained from microarrays or sequencing. This analysis helps identify which specific genes are being expressed or activated during stem cell differentiation.
By studying the gene expression patterns during stem cell differentiation, researchers can gain insights into the molecular processes underlying cellular development and function.