Identification and characterization of microRNAs expressed in the African malaria vector Anopheles funestus life stages using high throughput sequencing.
BACKGROUND
Over the past several years, thousands of microRNAs (miRNAs) have been identified in the genomes of various insects through cloning and sequencing or even by computational prediction. However, the number of miRNAs identified in anopheline species is low and little is known about their role. The mosquito Anopheles funestus is one of the dominant malaria vectors in Africa, which infects and kills millions of people every year. Therefore, small RNA molecules isolated from the four life stages (eggs, larvae, pupae and unfed adult females) of An. funestus were sequenced using next generation sequencing technology.


RESULTS
High throughput sequencing of four replicates in combination with computational analysis identified 107 mature miRNA sequences expressed in the An. funestus mosquito. These include 20 novel miRNAs without sequence identity in any organism and eight miRNAs not previously reported in the Anopheles genus but are known in non-anopheles mosquitoes. Finally, the changes in the expression of miRNAs during the mosquito development were determined and the analysis showed that many miRNAs have stage-specific expression, and are co-transcribed and co-regulated during development.


CONCLUSIONS
This study presents the first direct experimental evidence of miRNAs in An. funestus and the first profiling study of miRNA associated with the maturation in this mosquito. Overall, the results indicate that miRNAs play important roles during the growth and development. Silencing such molecules in a specific life stage could decrease the vector population and therefore interrupt malaria transmission.
SA Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Robert Sobukwe Road, Cape Town, 7535, South Africa.|Sequencing Core Facility, National Institute for Communicable Diseases, National Health Laboratory Service, 1 Modderfontein Road, Johannesburg, 2131, South Africa.
Mushal
M
Allam
Vector Control Reference Laboratory, Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, 1 Modderfontein Road, Johannesburg, 2131, South Africa.
Belinda L
BL
Spillings
Vector Control Reference Laboratory, Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, 1 Modderfontein Road, Johannesburg, 2131, South Africa.|Faculty of Health Sciences, Wits Research Institute for Malaria, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, 2000, South Africa.|Vector Biology & Control Unit, Blue Nile National Institute for Communicable Disease, Wad Medani, Sudan.
Hiba
H
Abdalla
SA Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Robert Sobukwe Road, Cape Town, 7535, South Africa.
Darlington
D
Mapiye
Vector Control Reference Laboratory, Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, 1 Modderfontein Road, Johannesburg, 2131, South Africa.|Faculty of Health Sciences, Wits Research Institute for Malaria, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, 2000, South Africa.
Lizette L
LL
Koekemoer
SA Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Robert Sobukwe Road, Cape Town, 7535, South Africa. alan@sanbi.ac.za.
Alan
http://orcid.org/0000-0002-0420-2916
A
Christoffels
D000349:Africa; D000818:Animals; D000852:Anopheles / Q000235:genetics* / Q000254:growth & development*; D005260:Female; D020869:Gene Expression Profiling; D059014:High-Throughput Nucleotide Sequencing; D008018:Life Cycle Stages; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D000072138:Mosquito Vectors / Q000235:genetics* / Q000254:growth & development*
D035683:MicroRNAs
Anopheles funestus; Malaria; MicroRNA; Non-coding RNA; Vector-borne diseases