In eukaryotes, cellular RNAs are produced by three nuclear RNA polymerases (RNAPI, II, and III), which are multisubunit complexes. They share structural and functional features, although they are specialized in the synthesis of specific RNAs. RNAPII transcribes the vast majority of cellular RNAs, including mRNAs and a large number of noncoding RNAs. The structure of RNAPII is highly conserved in all eukaryotes, consisting of 12 subunits (Rpb1-12) organized into five structural modules, among which the Rpb4 and Rpb7 subunits form the stalk. Early studies suggested an accessory role for Rpb4, because is required for specific gene transcription pathways. Far from this initial hypothesis, it is now well established that the Rpb4/7 heterodimer plays much wider roles in gene expression regulation. It participates in nuclear and cytosolic processes ranging from transcription to translation and mRNA degradation in a cyclical process. For this reason, Rpb4/7 is considered a coordinator of gene expression. New functions have been added to the list of stalk functions during transcription, which will be reviewed herein: first, a role in the maintenance of proper RNAPII phosphorylation levels, and second, a role in the establishment of a looped gene architecture in actively transcribed genes.

在真核生物中，细胞RNA是由三种核苷多聚体复合物核RNA聚合酶（RNAPI，II和III）产生的。尽管它们专门用于合成特定的RNA，但是它们具有结构和功能特征。RNAPII转录绝大多数细胞RNA，包括mRNA和大量非编码RNA。RNAPII的结构在所有真核生物中都是高度保守的，由12个亚基（Rpb1-12）组成五个结构模块，其中Rpb4和Rpb7亚基构成茎。早期研究表明Rpb4有辅助作用，因为特定基因转录途径需要Rpb4。到目前为止，Rpb4 / 7异二聚体在基因表达调控中起着更广泛的作用。它参与循环过程中从转录到翻译和mRNA降解的核和胞质过程。因此，Rpb4 / 7被认为是基因表达的协调者。新功能已添加到转录过程中的茎功能列表中，这里将对其进行回顾：首先，在维持适当的RNAPII磷酸化水平中的作用，其次，在活跃转录的基因中建立环状基因结构的作用。