Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics

Sanders - Genetic Analysis: An Integrated Approach 3rd Edition

Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook

Sanders 3rd Edition

Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics

Problem 2

Chapter 14, Problem 2

You conduct a study in which the transcriptional fusion of regulatory sequences of a particular gene with a reporter gene results in relatively uniform expression of the reporter gene in all cells of an organism. A translational fusion with the same gene shows reporter gene expression only in the nucleus of a specific cell type. Discuss some biological causes for the difference in expression patterns of the two transgenes.

Verified step by step guidance

Understand the difference between transcriptional and translational fusions: A transcriptional fusion involves linking the regulatory sequences of a gene (e.g., promoter and enhancer regions) to a reporter gene, which reflects where the gene is transcribed. A translational fusion, on the other hand, links the coding sequence of the gene to the reporter gene, allowing the reporter to mimic the protein's localization and expression pattern.

Analyze the uniform expression in the transcriptional fusion: The uniform expression of the reporter gene in all cells suggests that the regulatory sequences of the gene are active in all cells, driving transcription of the reporter gene. This indicates that the gene's transcriptional control elements are not restricted to specific cell types.

Consider the restricted expression in the translational fusion: The translational fusion shows reporter gene expression only in the nucleus of a specific cell type. This suggests that the protein encoded by the gene is localized to the nucleus and is expressed only in certain cell types, likely due to post-transcriptional regulation or cell-specific translation.

Discuss potential biological causes for the difference: The difference in expression patterns could be due to post-transcriptional regulatory mechanisms, such as mRNA stability, translation efficiency, or protein localization signals. For example, the gene may have a nuclear localization signal (NLS) that directs the protein to the nucleus, and this signal is only functional in specific cell types.

Conclude with the importance of regulatory levels: This difference highlights the complexity of gene regulation, where transcriptional control determines where a gene is transcribed, while post-transcriptional and translational mechanisms, including protein localization, determine where and how the protein functions within the organism.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Transcriptional Fusion

Transcriptional fusion involves linking the regulatory sequences of a gene to a reporter gene, allowing researchers to study the gene's expression patterns. This method reveals how the gene is activated and regulated across different cell types, as the reporter gene's expression reflects the activity of the promoter and enhancer elements controlling it.

Translational Fusion

Translational fusion combines the coding sequence of a gene with a reporter gene, which can affect the localization and stability of the resulting protein. This approach provides insights into the protein's expression and function within specific cellular compartments, such as the nucleus, highlighting how post-transcriptional modifications and localization signals influence protein behavior.

Cell Type-Specific Regulation

Cell type-specific regulation refers to the mechanisms that control gene expression differently in various cell types. Factors such as transcription factors, chromatin structure, and signaling pathways can lead to distinct expression patterns, explaining why a reporter gene may be uniformly expressed in all cells when linked transcriptionally, but only in specific cells when linked translationally.

Recommended video:

Guided course

03:51

GAL Regulation

Related Practice

Textbook Question

Go to the website http://www.cancer.gov and select 'Cancer Types' on the top menu bar. Scroll down to 'Breast Cancer' and click. Select 'Cases & Prevention' from the options. Click 'More information' and select 'BRCA Mutations: Cancer Risk and Genetic Testing'. Use the information on this page to answer the following questions. What features of family history increase the likelihood that a woman will have a harmful mutation of BRCA1 or BRCA2?

views

Textbook Question

The inheritance of certain mutations of BRCA1 can make it much more likely that a woman will develop breast or ovarian cancer in her lifetime. In addition to inheriting a BRCA1 mutation, what else must happen for a woman to develop breast or ovarian cancer?

Textbook Question

What are the advantages and disadvantages of using GFP versus lacZ as a reporter gene in mice, C. elegans, and Drosophila?

Textbook Question

Discuss the similarities and differences between forward and reverse genetic approaches, and when you would choose to utilize each of the approaches.

views

Textbook Question

Using the data in Table B, calculate the average number of kilobase (kb) pairs per centimorgan in the six multicellular eukaryotic organisms. How would this information influence strategies to clone genes known only by a mutant phenotype in these organisms?

Textbook Question

What are the advantages and disadvantages of using insertion alleles versus alleles generated by chemicals (as in TILLING) in reverse genetic studies?