Knockdown of the Plasmodium falciparum SURFIN4.1 antigen leads to an increase of its cognate transcript

• Published in: PloS one Vol. 12; no. 8; p. e0183129
• Main Authors: Macedo-Silva, Tatiane, Araujo, Rosana Beatriz Duque, Meissner, Kamila Anna, Fotoran, Wesley Luzetti, Medeiros, Márcia Melo, de Azevedo, Mauro Ferreira, Wunderlich, Gerhard
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 11-08-2017; Public Library of Science (PLoS)
• Subjects: Alleles; Antigens; Antigens, Protozoan - genetics; Antigens, Protozoan - metabolism; Biology and Life Sciences; Blood; Cellular proteins; Change detection; Cloning, Organism; Destabilization; Dihydrofolate reductase; Erythrocytes; Erythrocytes - parasitology; Feedback; Feedback, Physiological; Gene expression; Gene Expression Regulation; Gene Knockdown Techniques; Genes; Genetic aspects; Genomes; Half-Life; Health aspects; Humans; Life Cycle Stages - genetics; Malaria; Medicine and Health Sciences; Membrane proteins; Morpholines - pharmacology; Parasites; Parasitology; Plasmodium falciparum; Plasmodium falciparum - genetics; Plasmodium falciparum - growth & development; Plasmodium falciparum - metabolism; Polymerase chain reaction; Properties; Protein Isoforms - antagonists & inhibitors; Protein Isoforms - genetics; Protein Isoforms - metabolism; Proteins; Research and Analysis Methods; RNA Stability; RNA, Messenger - agonists; RNA, Messenger - genetics; RNA, Messenger - metabolism; Science; Sexual stages; Surf; Switching; Transcription; Transfection; Vector-borne diseases; Virulence; Virulence (Microbiology); Brazil
• DOI: 10.1371/journal.pone.0183129
• EISSN: 1932-6203

The genome of the malaria parasite Plasmodium falciparum contains the surf gene family which encodes large transmembrane proteins of unknown function. While some surf alleles appear to be expressed in sexual stages, others occur in asexual blood stage forms and may be associated to virulence-associated processes and undergo transcriptional switching. We accessed the transcription of surf genes along multiple invasions by real time PCR. Based on the observation of persistent expression of gene surf4.1, we created a parasite line which expresses a conditionally destabilized SURFIN4.1 protein. Upon destabilization of the protein, no interference of parasite growth or morphological changes were detected. However, we observed a strong increase in the transcript quantities of surf4.1 and sometimes of other surf genes in knocked-down parasites. While this effect was reversible when SURFIN4.1 was stabilized again after a few days of destabilization, longer destabilization periods resulted in a transcriptional switch away from surf4.1. When we tested if a longer transcript half-life was responsible for increased transcript detection in SURFIN4.1 knocked-down parasites, no alteration was found compared to control parasite lines. This suggests a specific feedback of the expressed SURFIN protein to its transcript pointing to a novel type of regulation, inedited in Plasmodium.