Autophagy-related genes from a tick, Haemaphysalis longicornis.
Ticks are gorging-fasting organisms;(1) their life cycle is characterized by alternate off-host (starvation) and on-host (meal) conditions. Their generation time is estimated in several years and many ticks spend more than 95% of their life off the host. They seem to have a unique strategy to endure the off-host state for a long period. Thus, we focused on autophagy, which is induced by starvation and is essential for extension of the lifespan,(2-4) and hypothesized that ticks also have a system of autophagy to overcome the starved condition. Recently, we showed the existence of a homologue of an ATG gene, ATG12, and its expression pattern from nymphal to adult stages in a three-host tick, Haemaphysalis longicornis. The expression level of HlATG12 was downregulated at the beginning of feeding and was highest at 3 months after engorgement. In addition, the HlAtg12 protein was localized to the region around granule-like structures within midgut cells of unfed adults. These results indicate that HlATG12 functions during unfed stages. Here, a potential role of autophagy in unfed ticks is discussed with regard to reports in other animals, such as yeast, mammal, and fruit fly.
Umemiya
Rika
R
Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.
Matsuo
Tomohide
T
Hatta
Takeshi
T
Sakakibara
Shin-Ichi
S
Boldbaatar
Damdinsuren
D
Fujisaki
Kozo
K
D000818:Animals; D001343:Autophagy / Q000235:genetics*; D005260:Female; D005508:Food Deprivation; D017344:Genes, Insect; D008018:Life Cycle Stages; D013987:Ticks / Q000235:genetics / Q000502:physiology