HSUR
Encyclopedia
HSURs are viral small regulatory RNAs
. They are found in Herpesvirus saimiri which is responsible for aggressive T-cell leukemia
s in primate
s. They are nuclear RNAs which bind host protein
s to form small nuclear ribonucleoproteins
(snRNPs). The RNAs are 114-143 nucleotide
s in length and the HSUR family has been subdivided into HSURs numbered 1 to 7. The function of HSURs has not yet been identified; they do not affect transcription so are thought to act post-transciptionally, potentially influencing the stability of host mRNAs.
HSUR1 and 2 are the most conserved members of the family within HSV subgroups. HSUR1 has been shown to bind the host heterogeneous ribonucleoprotein particle
protein hnRNPD in vivo. Other HSURs bind HuR/ELAVL1
. They are transcribed by RNA polymerase II
with promoters similar to that of U RNAs
Features shared by all HSURs include:
A proposed role for HSURs is that they use the RNAi
pathway to manipulate host-cell gene expression. One identified miRNA
which responds to HSURs is miR-27
.
Non-coding RNA
A non-coding RNA is a functional RNA molecule that is not translated into a protein. Less-frequently used synonyms are non-protein-coding RNA , non-messenger RNA and functional RNA . The term small RNA is often used for short bacterial ncRNAs...
. They are found in Herpesvirus saimiri which is responsible for aggressive T-cell leukemia
T-cell leukemia
T-cell leukemia describes several different types of lymphoid leukemia which affect T cells.Types include:* Large granular lymphocytic leukemia* Adult T-cell leukemia/lymphoma* T-cell prolymphocytic leukemia...
s in primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
s. They are nuclear RNAs which bind host protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s to form small nuclear ribonucleoproteins
SnRNP
snRNPs , or small nuclear ribonucleoproteins, are RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome, a large RNA-protein molecular complex upon which splicing of pre-mRNA occurs...
(snRNPs). The RNAs are 114-143 nucleotide
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
s in length and the HSUR family has been subdivided into HSURs numbered 1 to 7. The function of HSURs has not yet been identified; they do not affect transcription so are thought to act post-transciptionally, potentially influencing the stability of host mRNAs.
HSUR1 and 2 are the most conserved members of the family within HSV subgroups. HSUR1 has been shown to bind the host heterogeneous ribonucleoprotein particle
Heterogeneous ribonucleoprotein particle
Heterogeneous nuclear ribonucleoproteins are complexes of RNA and protein present in the cell nucleus during gene transcription and subsequent post-transcriptional modification of the newly synthesized RNA . The presence of the proteins bound to a pre-mRNA molecule serves as a signal that the...
protein hnRNPD in vivo. Other HSURs bind HuR/ELAVL1
ELAVL1
ELAV-like protein 1 or HuR is a protein that in humans is encoded by the ELAVL1 gene.-Further reading:...
. They are transcribed by RNA polymerase II
RNA polymerase II
RNA polymerase II is an enzyme found in eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA. A 550 kDa complex of 12 subunits, RNAP II is the most studied type of RNA polymerase...
with promoters similar to that of U RNAs
Features shared by all HSURs include:
- 5´-trimethylguanosine caps5' capThe 5' cap is a specially altered nucleotide on the 5' end of precursor messenger RNA and some other primary RNA transcripts as found in eukaryotes. The process of 5' capping is vital to creating mature messenger RNA, which is then able to undergo translation...
- 3' terminal stem-loopStem-loopStem-loop intramolecular base pairing is a pattern that can occur in single-stranded DNA or, more commonly, in RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same strand, usually complementary in nucleotide sequence when read in opposite directions,...
s - canonical Sm protein-binding site (AUUUUUG)
A proposed role for HSURs is that they use the RNAi
RNAI
RNAI is a non-coding RNA that is an antisense repressor of the replication of some E. coli plasmids, including ColE1. Plasmid replication is usually initiated by RNAII, which acts as a primer by binding to its template DNA. The complementary RNAI binds RNAII prohibiting it from its initiation role...
pathway to manipulate host-cell gene expression. One identified miRNA
Mirna
Mirna may refer to:geographical entities* Mirna , a river in Istria, Croatia* Mirna , a river in Slovenia, tributary of the river Sava* Mirna , a settlement in the municipality of Mirna in Southeastern Sloveniapeople...
which responds to HSURs is miR-27
MiR-27
miR-27 is a family of microRNA precursors found in animals, including humans. MicroRNAs are typically transcribed as ~70 nucleotide precursors and subsequently processed by the Dicer enzyme to give a ~22 nucleotide product...
.