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.

RNA Polymerase Mutation       Effect(s)
RNA pol I                                  _______________
RNA pol II                                 _______________
RNA pol III                                _______________
snRNA                                      _______________

Some rRNA is not synthesized.

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 analyzing 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, the effects can range from benign to detrimental, potentially leading to the loss of function of the encoded protein. 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.

RNA Synthesis and Function

RNA synthesis is a critical process in gene expression, where DNA is transcribed into RNA, which then serves various functions in the cell. For instance, mRNA carries genetic information from DNA to ribosomes for protein synthesis, while rRNA is a key component of ribosomes. Disruptions in RNA synthesis due to mutations in RNA polymerases can lead to insufficient production of essential RNA molecules, affecting overall cellular function and viability.