Shaping the Genome with Non-coding RNAs
Pp. 62-90 (29)
Xue Qing David Wang, Jennifer Lynn Crutchley and Josée Dostie
The human genome must be tightly packaged in order to fit inside the
nucleus of a cell. Genome organization is functional rather than random, which allows
for the proper execution of gene expression programs and other biological processes.
Recently, three-dimensional chromatin organization has emerged as an important
transcriptional control mechanism. For example, enhancers were shown to regulate
target genes by physically interacting with them regardless of their linear distance and
even if located on different chromosomes. These chromatin contacts can be measured
with the “chromosome conformation capture” (3C) technology and other 3C-related
techniques. Given the recent innovation of 3C-derived approaches, it is not surprising
that we still know very little about the structure of our genome at high-resolution. Even
less well understood is whether there exist distinct types of chromatin contacts and
importantly, what regulates them. A new form of regulation involving the expression of
long non-coding RNAs (lncRNAs) was recently identified. lncRNAs are a very
abundant class of non-coding RNAs that are often expressed in a tissue-specific manner.
Although their different subcellular localizations points to their involvement in
numerous cellular processes, it is clear that lncRNAs play an important role in
regulating gene expression. They have been shown to bind several ribonucleoprotein
complexes including the polycomb repression complex, which modify chromatin
epigenetically by transferring histone marks, but how they control transcription however
is mostly unknown. In this review, we provide an overview of known lncRNA
transcription regulation activities. We also discuss potential mechanisms by which
ncRNAs might exert three-dimensional transcriptional control and what recent studies
have revealed about their role in shaping our genome.
Chromatin, chromosome conformation capture, epigenetics, gene
regulation, histone marks, non-coding RNA, polycomb repression complex,
ribonucleoprotein complex, three-dimensional chromatin organization, transcription.
Department of Biochemistry, and Goodman Cancer Research Center, McGill University, 3655 Promenade Sir-William-Osler, Room 815A, Montréal, Québec, H3G1Y6, Canada.