Assume that a mutation affects the gene for each of the following eukaryotic RNA polymerases. Match each mutation with the possible effects from the list provided. More than one effect is possible for each mutation.

Some rRNA is not synthesized.

Verified step by step guidance

1. Understand the roles of the three eukaryotic RNA polymerases: RNA polymerase I synthesizes most rRNA (ribosomal RNA), RNA polymerase II synthesizes mRNA (messenger RNA) and some snRNA (small nuclear RNA), and RNA polymerase III synthesizes tRNA (transfer RNA), 5S rRNA, and some snRNA.
2. Analyze the mutation effects: If some rRNA is not synthesized, this suggests a mutation in RNA polymerase I, as it is responsible for producing the majority of rRNA.
3. Match RNA polymerase II with its effects: A mutation in RNA polymerase II would affect the synthesis of mRNA and some snRNA, potentially disrupting protein-coding gene expression and RNA splicing.
4. Match RNA polymerase III with its effects: A mutation in RNA polymerase III would affect the synthesis of tRNA, 5S rRNA, and some snRNA, potentially disrupting translation and ribosome assembly.
5. Determine the effect on snRNA synthesis: Since snRNA is synthesized by both RNA polymerase II and RNA polymerase III, a mutation in either of these polymerases could lead to a reduction in snRNA production, affecting RNA splicing.

Key Concepts

Eukaryotic RNA Polymerases

Eukaryotic cells contain three main types of RNA polymerases: RNA polymerase I (RNA pol I), RNA polymerase II (RNA pol II), and RNA polymerase III (RNA pol III). Each polymerase is responsible for synthesizing different types of RNA; RNA pol I primarily synthesizes ribosomal RNA (rRNA), RNA pol II synthesizes messenger RNA (mRNA) and some small nuclear RNAs (snRNA), and RNA pol III synthesizes transfer RNA (tRNA) and other small RNAs. Understanding the specific functions of these polymerases is crucial for predicting the effects of mutations.

Mutations and Their Effects

Mutations are changes in the DNA sequence that can affect gene function. Depending on the type and location of the mutation, effects can range from benign to detrimental, potentially leading to the loss of function of the encoded protein or altered gene expression. In the context of RNA polymerases, mutations can disrupt the synthesis of specific RNA types, impacting cellular processes such as protein synthesis and gene regulation.

snRNA and Its Role

Small nuclear RNA (snRNA) is a class of RNA molecules that play a critical role in the splicing of pre-mRNA in eukaryotic cells. They are components of the spliceosome, a complex responsible for removing introns from pre-mRNA transcripts. Mutations affecting snRNA can lead to improper splicing, resulting in the production of nonfunctional or dysfunctional proteins, which can have significant consequences for cellular function and organismal health.