熱帯医学研究所カレトンリチャード准教授、ジュンカオ博士(中国)、アーナブペイン博士(サウジアラビア)らの共同研究グループは、四日熱マラリア原虫と卵形マラリア原虫の全ゲノムシーケンス解析を行ない、それらの全ゲノム情報を解読しました。 この2つのマラリア種は熱帯地域の深刻な病であるにも関わらず、十分な量のDNAを確保するのが難しいために今までその遺伝情報が分かっていませんでした。今回の全ゲノム情報の発表は、今後新しい治療薬とワクチン開発に繋がるものと思われます。 成果は、国際科学雑誌『International Journal for Parasitology電子版』(2016年7月5日)に発表しました。 論文タイトル Genome-scale comparison of expanded gene
families in Plasmodium ovale wallikeri
and Plasmodium ovale curtisi
with Plasmodium malariae and with other Plasmodium
species アブストラクト Malaria in humans is caused by six species
of Plasmodium parasites, of which the nuclear genome sequences for the two
Plasmodium ovale spp., P. ovale
curtisi and P. ovale wallikeri, and Plasmodium malariae
have not yet been analyzed. Here we present an analysis of the nuclear genome
sequences of these three parasites, and describe gene family expansions
therein. Plasmodium ovale curtisi
and P. ovale wallikeri are
genetically distinct but morphologically indistinguishable and have sympatric
ranges through the tropics of Africa, Asia and Oceania. Both P. ovale spp. show expansion of the surfin
variant gene family, and an amplification of the Plasmodium interspersed repeat
(pir) superfamily which results in an approximately
30% increase in genome size. For comparison, we have also analyzed the draft
nuclear genome of P. malariae, a malaria parasite
causing mild malaria symptoms with a quartan life
cycle, long-term chronic infections, and wide geographic distribution.
Plasmodium malariae shows only a moderate level of expansion
of pir genes, and unique expansions of a highly
diverged transmembrane protein family with over 550 members and the gamete
P25/27 gene family. The observed diversity in the P. ovale
wallikeri and P. ovale curtisi surface antigens, combined with their phylogenetic
separation, supports consideration that the two parasites be given species
status. |