Evidence for Karyogamy and Exchange of Genetic Material in the Binucleate Intestinal Parasite Giardia intestinalis

@article{Poxleitner2008EvidenceFK,
  title={Evidence for Karyogamy and Exchange of Genetic Material in the Binucleate Intestinal Parasite Giardia intestinalis},
  author={Marianne K. Poxleitner and Meredith L Carpenter and Joel J Mancuso and Chung-Ju Rachel Wang and Scott C. Dawson and William Zacheus Cande},
  journal={Science},
  year={2008},
  volume={319},
  pages={1530 - 1533}
}
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… Expand
Nuclear inheritance and genetic exchange without meiosis in the binucleate parasite Giardia intestinalis
TLDR
It is demonstrated that the cyst is formed from a single trophozoite by a mitotic division without cytokinesis and not by the fusion of two Trophozoites, and nuclear sorting does not appear to be a mechanism by which Giardia reduces heterozygosity between its nuclei. Expand
Nuclear inheritance and genetic exchange in Giardia intestinalis, a divergent eukaryote with two nuclei
TLDR
This dissertation describes the development of morpholinos as a new tool for gene knockdown in Giardia and demonstrates that nuclear fusion and genetic exchange occur between nuclei in the cyst, a process the authors have termed diplomixis. Expand
Unequal distribution of genes and chromosomes refers to nuclear diversification in the binucleated Giardia intestinalis.
TLDR
It is demonstrated by fluorescence in situ hybridization that several genes from chromosome 5 are lost in one of the two nuclei of the WBc6 Giardia line, offering the first methodical approach to differentiating the two, so far indistinguishable nuclei. Expand
Giardia duodenalis: genetic recombination and its implications for taxonomy and molecular epidemiology.
TLDR
This review summarizes the experimental approaches and the results obtained, and discusses the implications of recombination from the standpoint of the taxonomy and molecular epidemiology of this widespread pathogen. Expand
Double peaks reveal rare diplomonad sex.
TLDR
It is argued, in contrast to common assumptions, that allelic differences indicate recent sexual events, and isolates that have divided asexually for many generations have lost their allelic variation owing to within-cell recombination. Expand
Transcription of meiotic-like-pathway genes in Giardia intestinalis.
TLDR
Semiquantitative RT-PCR analysis was used to assess the transcription pattern of three meiosis-like-specific genes involved in homologues recombination in Giardia intestinalis, and suggests that expression of some of the genes is regulated during encystation process. Expand
Transcription and Recombination in Giardia
TLDR
The answers to how Giardia handles transcription and recombination with its minimalist approach may also shed light on the more complex systems used by other organisms. Expand
Identification of the meiotic life cycle stage of Trypanosoma brucei in the tsetse fly
TLDR
It is demonstrated that three functionally distinct, meiosis-specific proteins are expressed in the nucleus of a single specific cell type, defining a previously undescribed developmental stage occurring within the tsetse fly salivary gland. Expand
A ‘parameiosis’ drives depolyploidization and homologous recombination in Candida albicans
TLDR
Results indicate that C. albicans CCL represents a ‘parameiosis’ that blurs the conventional boundaries between mitosis and meiosis and reveal parallels with depolyploidization in mammalian cells and provide potential insights into the evolution of meiosis. Expand
Homologous Recombination Occurs in Entamoeba and Is Enhanced during Growth Stress and Stage Conversion
TLDR
The up regulation of mitotic and meiotic HR genes in Entamoeba during serum starvation, and encystation is shown, and recombination between chromosomal inverted repeats is demonstrated. Expand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 18 REFERENCES
Population Genetics Provides Evidence for Recombination in Giardia
TLDR
A multilocus sequence evaluation of the genotypes A2 reference strain, JH, and five genotype A2 isolates from a highly endemic area in Peru provided genetic data supportive of sexual reproduction in Giardia. Expand
Genomic Minimalism in the Early Diverging Intestinal Parasite Giardia lamblia
The genome of the eukaryotic protist Giardia lamblia, an important human intestinal parasite, is compact in structure and content, contains few introns or mitochondrial relics, and has simplifiedExpand
In situ analyses reveal that the two nuclei of Giardia lamblia are equivalent.
TLDR
The protozoan parasite Giardia lamblia has the unusual morphology of bearing two equal-sized nuclei, and it is shown that the two nuclei are equivalent with respect to the amount of DNA harbored in each nucleus, the presence of ribosomal DNA sequences, and the transcriptional activity. Expand
Three-dimensional analysis of mitosis and cytokinesis in the binucleate parasite Giardia intestinalis
TLDR
This analysis supports a nuclear migration model of mitosis with lateral chromosome segregation in the left-right axis and cytokinesis along the longitudinal plane (perpendicular to the spindles), ensuring that each daughter inherits one copy of each parental nucleus with mirror image symmetry. Expand
The Two Nuclei of Giardia Each Have Complete Copies of the Genome and Are Partitioned Equationally at Cytokinesis
ABSTRACT Giardia lamblia is medically important as a cause of diarrhea and malabsorption throughout the world and is thought to be one of the earliest-branching eukaryotes on a phylogenetic tree.Expand
A Phylogenomic Inventory of Meiotic Genes Evidence for Sex in Giardia and an Early Eukaryotic Origin of Meiosis
TLDR
The presence of five meiosis-specific genes indicates that Giardia is capable of meiotic and, thus, sexual reproduction, and the evolution of meiosis occurred early in eukaryotic evolution. Expand
Genome ploidy in different stages of the Giardia lamblia life cycle
TLDR
The nuclear and cellular genome ploidy of G. lamblia cells during all stages of the life cycle is determined and it is suggested that the newly excysted cell, for which the term ‘excyzoite’ is suggested, contains four nuclei. Expand
The Giardia lamblia trophozoite contains sets of closely related chromosomes.
TLDR
Densitometric comparisons of chromosome bands from known numbers of Plasmodium falciparum ring stage forms andknown numbers of Giardia trophozoites suggest that minor bands MBa and MBb are present in each Giardian trophozite. Expand
The HOP1 gene encodes a meiosis-specific component of yeast chromosomes
TLDR
It is demonstrated that the HOP1 gene is transcriptionally regulated during sporulation and that theHOP1 protein is situated along the lengths of meiotic chromosomes, perhaps serving as a constituent of the synaptonemal complex. Expand
Biology of Giardia lamblia
  • R. D. Adam
  • Medicine, Biology
  • Clinical Microbiology Reviews
  • 2001
TLDR
The Giardia genome project promises to greatly increase the understanding of this interesting and enigmatic organism. Expand
...
1
2
...