Evidence for karyogamy and exchange of genetic material in the binucleate intestinal parasite Giardia intestinalis
Evidence for karyogamy and exchange of genetic material in the binucleate intestinal parasite Giardia intestinalis
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DOI：
10.1126/science.1153752
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发表时间：
2008-03-14
期刊：
影响因子：
56.9
通讯作者：
Cande, W. Zacheus
中科院分区：
文献类型：
--
作者：
Poxleitner, Marianne K.;Carpenter, Meredith L.;Cande, W. Zacheus
双毛虫寄生虫肠贾第鞭毛虫含有两个功能相同的细胞核，它们在有丝分裂过程中独立遗传。尽管贾第鞭毛虫被认为是无性的，但其等位基因杂合性水平较低，表明两个核基因组可能交换遗传物质。用探针对附加型质粒进行的荧光原位杂交表明质粒在囊肿的细胞核之间转移，并且透射电子显微照片证明了囊肿核之间的融合。减数分裂特异性基因的贾第虫同源物的绿色荧光蛋白融合物定位于包囊的细胞核，但不定位于营养滋养体。这些数据表明，在贾第鞭毛虫包囊中发生了细胞核的融合或核配体，以及随后由减数分裂基因同源物促进的体细胞同源重组。
The diplomonad parasite Giardia intestinalis contains two functionally equivalent nuclei that are inherited independently during mitosis. Although presumed to be asexual, Giardia has low levels of allelic heterozygosity, indicating that the two nuclear genomes may exchange genetic material. Fluorescence in situ hybridization performed with probes to an episomal plasmid suggests that plasmids are transferred between nuclei in the cyst, and transmission electron micrographs demonstrate fusion between cyst nuclei. Green fluorescent protein fusions of giardial homologs of meiosis- specific genes localized to the nuclei of cysts, but not the vegetative trophozoite. These data suggest that the fusion of nuclei, or karyogamy, and subsequently somatic homologous recombination facilitated by the meiosis gene homologs, occur in the giardial cyst.