Question

Isoginkgetin is a cell-permeable chemical isolated from the Ginkgo biloba tree that binds to and inhibits snRNPs. (a) What types of problems would you anticipate in cells treated with isoginkgetin? (b) Would this be most problematic for \(E\). coli cells, yeast cells, or human cells? Why?

Short answer

Answer: The potential problems in cells treated with isoginkgetin include the disruption of the splicing process, accumulation of unprocessed pre-mRNA molecules, and synthesis of incomplete or non-functional proteins, affecting gene expression and cellular functions. Among E. coli, yeast, and human cells, human cells would be most affected by isoginkgetin treatment due to their more complex gene regulation and extensive mRNA splicing processes. E. coli cells would not be significantly affected as they lack mRNA splicing, while yeast cells, although affected, have less complexity than human cells.

Step-by-step solution

Understanding snRNPs

Small nuclear ribonucleoproteins (snRNPs) are complexes made up of small nuclear RNA (snRNA) molecules and proteins. snRNPs play a crucial role in the splicing process, during which introns are removed from pre-mRNA molecules to form mature mRNA. This process is essential for proper gene expression and the synthesis of functional proteins.

Potential problems in cells treated with isoginkgetin

As isoginkgetin binds to and inhibits snRNPs, it can interfere with the splicing process, leading to the following problems in cells: 1. Accumulation of unprocessed pre-mRNA molecules, which can disrupt gene expression. 2. Production of incomplete or non-functional proteins due to the presence of introns in mRNA molecules.

Identifying the most affected cell type

We now need to determine which cell type would be most problematic when treated with isoginkgetin, considering E. coli, yeast, and human cells. E. coli cells are prokaryotic cells that lack a nucleus, and their mRNA molecules do not undergo splicing. Thus, E. coli cells should not be significantly affected by isoginkgetin treatment. Yeast cells are eukaryotic cells, and their mRNA molecules undergo splicing. Therefore, they may face problems when treated with isoginkgetin, as it can interfere with the splicing process. Human cells are also eukaryotic cells, and their mRNA molecules undergo extensive splicing. Moreover, human cells have more genes and more complex regulatory processes than yeast cells. Disruption of the splicing process in human cells can have severe consequences on gene expression and cellular function.

Answering the questions

(a) In cells treated with isoginkgetin, we would anticipate problems related to the splicing process. Accumulation of unprocessed pre-mRNA molecules and synthesis of incomplete or non-functional proteins could occur, affecting overall gene expression and cellular function. (b) Among E. coli cells, yeast cells, and human cells, isoginkgetin treatment would be most problematic for human cells. Since human cells have more genes and complex regulatory processes, the disruption of the splicing process would have a more significant impact on gene expression and cellular function than in yeast cells. On the other hand, E. coli cells are not expected to be significantly affected due to the lack of mRNA splicing in prokaryotic cells.

Key concepts

mRNA Splicing

The biological process known as mRNA splicing is a critical phase in the journey from DNA to protein. During splicing, non-coding regions of pre-messenger RNA (pre-mRNA) called introns are removed, leaving behind only the coding sequences, known as exons.

In a molecule like isoginkgetin that inhibits snRNPs, this will lead to a disruption in the splicing process, causing an accumulation of pre-mRNA that is not properly edited. Without accurate splicing, mRNA molecules can be dysfunctional or produce non-functional proteins, impacting the health and survival of eukaryotic cells, where splicing is a pivotal operation.

Gene Expression

Gene expression is the process by which the instructions in our DNA are converted into a functional product, typically a protein. This process is highly regulated and involves multiple steps, starting from transcription of DNA into RNA and culminating in the translation of that RNA into a protein.

When snRNPs are inhibited by substances like isoginkgetin, the result is an abnormal gene expression, as the essential splicing of pre-mRNA is compromised. This can lead to a cascade of effects in the cell: impeding protein production, altering cellular functions, and possibly causing diseases or disorders due to the malfunctioning proteins.

Eukaryotic Versus Prokaryotic Cells

Understanding the distinction between eukaryotic and prokaryotic cells is key to assessing the impact of molecules that interfere with splicing, like isoginkgetin. Eukaryotic cells, which include yeast and human cells, have a true nucleus and complex intracellular compartmentalization. They require mRNA splicing in their gene expression pathway. Prokaryotic cells, like those of E. coli, lack a nucleus and do not undergo splicing.

This fundamental difference explains why prokaryotic cells remain unaffected by snRNP inhibitors — they simply don't have the splicing machinery that the inhibitor targets. On the other hand, eukaryotic cells, especially those of humans with their extensive and complex splicing needs, are more vulnerable to disruptions caused by compounds hindering snRNP function.