We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress
Sign In
Advertise with Us
LGC Clinical Diagnostics

Download Mobile App




Long Noncoding RNAs Maintain Antigenic Variation in the Malaria Parasite

By LabMedica International staff writers
Posted on 11 Mar 2015
Print article
Image: Blood smear from a P. falciparum culture. Several red blood cells have ring stages inside them. Close to the center is a schizont and on the left a trophozoite (Photo courtesy of Wikimedia Commons).
Image: Blood smear from a P. falciparum culture. Several red blood cells have ring stages inside them. Close to the center is a schizont and on the left a trophozoite (Photo courtesy of Wikimedia Commons).
Control of DNA expression by long noncoding RNAs has been found to underlie antigenic variation, the mechanism by which the malaria parasite Plasmodium falciparum maintains its virulence and evades human immune attack.

Long noncoding RNAs (long ncRNAs, lncRNA) are non-protein coding transcripts longer than 200 nucleotides. This somewhat arbitrary limit distinguishes lncRNAs from small regulatory RNAs such as microRNAs (miRNAs), short interfering RNAs (siRNAs), Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), and other short RNAs. While lncRNAs are known to be involved in numerous biological roles including imprinting, epigenetic gene regulation, cell cycle and apoptosis, and metastasis and prognosis in solid tumors, their function in parasitic diseases has not been clarified.

Plasmodium falciparum expresses its primary virulence determinants in a mutually exclusive manner and evades human immune attack through switches in expression between different variants of a large gene family named var. Investigators at the Hebrew University of Jerusalem (Israel) sought an explanation as to how P. falciparum was able to express only one var gene at a time while the rest of the family was maintained silenced.

They reported in the February 17, 2015, online edition of the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS) that antisense lncRNAs initiating from var introns were associated with the single active var gene at the time in the cell cycle when the single var upstream promoter was active. These antisense transcripts were incorporated into chromatin, and expression of these antisense lncRNAs triggered activation of a silent var gene in a sequence- and dose-dependent manner. On the other hand, interference with these lncRNAs using complement peptide nucleic acid molecules downregulated the active var gene, erased the epigenetic memory, and induced expression switching.

Senior author Dr. Ron Dzikowski, professor of microbiology and molecular genetics at the Hebrew University of Jerusalem, said, “We believe this breakthrough has exposed the tip of the iceberg in understanding how the deadliest malaria parasite regulates the selective expression of its genes, enabling it to evade the immune system. Understanding the mechanisms by which the parasite evades immunity takes us closer to finding ways to either block this ability, or force the parasite to expose its entire antigenic repertoire and thus allow the human immune system to overcome the disease. Such findings can help pave the way for development of new therapies and vaccines for malaria.”

Related Links:

Hebrew University of Jerusalem 


Platinum Member
COVID-19 Rapid Test
OSOM COVID-19 Antigen Rapid Test
One Step HbA1c Measuring System
GREENCARE A1c
Complement 3 (C3) Test
GPP-100 C3 Kit
Gold Member
Real-time PCR System
GentierX3 Series

Print article

Channels

Clinical Chemistry

view channel
Image: Reaching speeds up to 6,000 RPM, this centrifuge forms the basis for a new type of inexpensive, POC biomedical test (Photo courtesy of Duke University)

POC Biomedical Test Spins Water Droplet Using Sound Waves for Cancer Detection

Exosomes, tiny cellular bioparticles carrying a specific set of proteins, lipids, and genetic materials, play a crucial role in cell communication and hold promise for non-invasive diagnostics.... Read more

Molecular Diagnostics

view channel
Image: MOF materials efficiently enrich cfDNA and cfRNA in blood through simple operational process (Photo courtesy of Science China Press)

Blood Circulating Nucleic Acid Enrichment Technique Enables Non-Invasive Liver Cancer Diagnosis

The ability to diagnose diseases early can significantly enhance the effectiveness of clinical treatments and improve survival rates. One promising approach for non-invasive early diagnosis is the use... Read more

Hematology

view channel
Image: The low-cost portable device rapidly identifies chemotherapy patients at risk of sepsis (Photo courtesy of 52North Health)

POC Finger-Prick Blood Test Determines Risk of Neutropenic Sepsis in Patients Undergoing Chemotherapy

Neutropenia, a decrease in neutrophils (a type of white blood cell crucial for fighting infections), is a frequent side effect of certain cancer treatments. This condition elevates the risk of infections,... Read more

Pathology

view channel
Image: The OvaCis Rapid Test discriminates benign from malignant epithelial ovarian cysts (Photo courtesy of INEX)

Intra-Operative POC Device Distinguishes Between Benign and Malignant Ovarian Cysts within 15 Minutes

Ovarian cysts represent a significant health issue for women globally, with up to 10% experiencing this condition at some point in their lives. These cysts form when fluid collects within a thin membrane... Read more
Copyright © 2000-2024 Globetech Media. All rights reserved.