Chapter 17.5, Problem 30CQ

Summary Introduction

To propose:

A mechanism for the inhibition of $\text{CK-B}$ translation in the U937D cells.

Introduction:

Eukaryotic $\text{mRNAs}$ have long $3^{\prime }$ UTR that often contains consensus sequences. $\text{CK-B}$ is an important enzyme in the cellular metabolism. U937D are cells that have lots of $\text{CK-B}$$\text{mRNAs}$ but no $\text{CK-B}$ enzyme. In such cells, the $\text{CK-B}$$\text{mRNA}$$5^{\prime }$ end is bound to ribosomes but $\text{mRNA}$ is not translated.

Summary Introduction

To explain:

The way in which introduction of short segments of RNA containing the 3’ UTR sequences that might remove that inhibition.

Introduction:

Researchers have introduced numerous short RNA segments containing $3^{\prime }$ UTR sequences only into U937D cells. As a result, these cells began to synthesize $\text{CK-B}$ but this does not affect the CK-B mRNA amount. The introduction of short segments did not stimulate the $\text{CK-B}$ synthesis, only the $3^{\prime }$ UTR sequences turned on the enzyme translation.