Characterization and molecularcloning of conjugation- regulating sex pheromones in homothallic Closterium
Characterization and molecularcloning of conjugation- regulating sex pheromones in homothallic Closterium
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同宗新月菌中接合调节性信息素的表征和分子克隆
DOI：
10.1093/pcp/pcq110
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
H
中科院分区：
文献类型：
--
作者：
Tsuchikane;Y.;Kokubun;Y. & Sekimoto;H
首次对同宗配合的新月藻中的结合调节信息素进行了分析。该复合体的成员是单细胞轮藻纲藻类，其中有两种接合孢子形成模式：异宗配合和同宗配合。新月藻的一个同宗配合系（命名为Kodama 20）通过来自一个营养细胞的两个姐妹配子囊细胞接合形成自交接合孢子。在培养正常密度细胞的培养基中，分别检测到对极低细胞密度（1× 102细胞ml-1）和正常细胞密度（1× 104细胞ml-1）细胞的结合促进和抑制活性。在60 ℃孵育10 min后，信息素活性下降至20%。信息素的释放和作用依赖于光。培养基经过凝胶过滤，两种活性物质的表观分子量均为17 kDa;这与之前报道的异宗配合性特异性信息素原生质体释放诱导蛋白（PR-IP）诱导剂的表观分子量相似。编码PR-IP诱导物的直向同源物的cDNA分离自同宗配合菌株。由酵母细胞产生的重组PR-IP诱导剂显示出接合促进活性。这些结果表明，同宗配合的菌株的接合是由异宗配合的性特异性信息素的直系同源物调节。
Conjugation-regulating pheromones were analyzed in homothallic Closterium for the first time. Members of the Closterium peracerosum–strigosum–littorale complex are unicellular charophycean algae in which there are two modes of zygospore formation: heterothallism and homothallism. A homothallic strain of Closterium (designation, kodama20) forms selfing zygospores via the conjugation of two sister gametangial cells derived from one vegetative cell. Conjugation-promoting and-suppressing activities, against cells at very low (1× 10 2 cells ml− 1) and normal (1× 10 4 cells ml− 1) cell density, respectively, were detected in the medium in which cells of a normal density had been cultured. Pheromone activities decreased to 20% after incubation at 60 C for 10 min. The release and action of the pheromones was dependent on light. The culture medium was subjected to gel filtration, and both active substances had an apparent molecular mass of 17 kDa; this was similar to that previously reported for the heterothallic sex-specific pheromone protoplast-release-inducing protein (PR-IP) Inducer. cDNAs encoding the orthologs of PR-IP Inducer were isolated from the homothallic strain. Recombinant PR-IP Inducers produced by yeast cells showed conjugation-promoting activity. These results indicate that conjugation of the homothallic strain is regulated by an ortholog of a heterothallic sex-specific pheromone.