The Little Elongation Complex Functions at Initiation and Elongation Phases of snRNA Gene Transcription

Abstract

SUMMARY The small nuclear RNA (snRNA) genes have been widely used as a model system for understanding transcriptional regulation due to the unique aspects of their promoter structure, selectivity for either RNA Polymerase (Pol) II or III, and because of their unique mechanism of termination that is tightly linked with the promoter. Recently, we identified the Little Elongation Complex (LEC) in Drosophila that is required for the expression of Pol II-transcribed snRNA genes. Here, using Drosophila and mammalian systems, we provide genetic and molecular evidence that LEC functions in at least two phases of snRNA transcription: an initiation step requiring the ICE1 subunit, and an elongation step requiring ELL.

DSIF and NELF interact with Integrator to specify the correct post-transcriptional fate of snRNA genes

“…Since DSIF functions as a dual regulator of transcription elongation for protein-coding genes, it may play a similar role in regulating the U1 gene. It may seem strange that an elongation factor is critical for the synthesis of such a small RNA; however, recent studies have shown that the little elongation complex, which comprises ELL and a few other subunits, is also required for the initiation and elongation phases of snRNA gene transcription 40,41 . It is not immediately clear why elongation factors are required for transcription of short snRNA genes.…”

Epigenetics of hematopoiesis and hematological malignancies

“…2C; Lin et al 2010). ELL is also found in the little elongation complex (LEC), which specifically regulates distinct stages of small nuclear RNA transcription, essential housekeeping functions that are likely compensated for by the wild-type allele of ELL in leukemia Hu et al 2013b).…”

p53 represses the transcription of snRNA genes by preventing the formation of little elongation complex

“…It has been reported that two ELL/EAF-containing complexes, super elongation complex (SEC) and little elongation complex (LEC), specifically regulate the transcription of distinct genes [4,5]. LEC is composed of multiple subunits including the ELL/EAF component, KIAA0947, NARG2 and ZC3H8 [3,6,7].…”

“…Recently, we showed that human Mediator subunit MED26 contributes to the recruitment of LEC to a subset of snRNA genes [6]. ICE1 is one of the central components for the assembly of LEC [5]. It has been shown that LEC plays a role in both the transcription initiation and elongation phases of snRNA gene transcription [5].…”

“…ICE1 is one of the central components for the assembly of LEC [5]. It has been shown that LEC plays a role in both the transcription initiation and elongation phases of snRNA gene transcription [5]. However, the detailed function of ICE1 and ICE2 in LEC has not been elucidated.…”