Unraveling the Mechanism of Cryptic Sexual Cycle Development in Amoeba, Cochliopodium, using Comparative Transcriptome and Immunocytochemistry The proposed work aims to unravel the cytological and genetic underlying of the cryptic sexual life cycle of an amoeboid lineage, Cochliopodium. Sexual reproduction is highly beneficial in eukaryotes by enabling them to increase: genetic diversity, fitness under selective pressure and virulence as in pathogenic eukaryotes. However, sexuality in most microbial eukaryotes is poorly understood. This is mainly due to their diverse quality and complex life cycle. Unlike most other amoebae including E. histolytica that are assumed to engage in sex during the dormant, cyst stage (a challenge for experimental study), Cochliopodium undergoes nuclear fusion in the actively growing vegetative stage. This makes it an ideal candidate for investigative work involving live experimentation. The proposed work will test three interrelated hypotheses including genetic mechanisms of sexual development, mechanisms of genome reduction and genetic recombination and mating system in Cochliopodium. We will use a combination of methods including comparative transcriptome obtained using next generation sequencing, cytological evidence on targeted sex genes using immunocytochemistry (ICC), and a series of culturing experimentation to understand mating system in Cochliopodium. We have already built bioinformatics pipeline and custom scripts to assemble and analyze the genetic data. Newly available statistical tools for de novo data will be used for comparative gene expression analysis. Addressing the proposed hypotheses will enable: (a) uncover cytological signatures of the stages of sexual development in Cochliopodium, (b) shed light on the molecular mechanisms of a possible cryptic sexual life cycle in Cochliopodium and others, (c) understand mechanisms of genome reduction and genetic recombination in cryptic life cycles, (d) exploration of targets that might be used to combat eukaryotic pathogens, and (e) provide insights into the origin and evolution of sexuality in microbial eukaryotes.
Amoeboids lineages provide powerful model systems to understand many cellular processes (e.g. cytokinesis, cell motility, signal transduction, and cell differentiation) that play significant roles in human health and disease systems; in fact, some amoeboids are directly implicated in human infectious diseases. The proposed work focuses on one of the most important biological processes, sexual reproduction, proven to enhancing pathogen virulence and adaptation to new environments. Understanding the cellular and molecular mechanisms of the sexual life cycle in eukaryotic microbes will generate insights about the emergence of new pathogens, and based on possible new evidence of sex-related genes in these microbes, may help to identify new targets for therapeutic drugs.
| Tekle, Yonas I; Wood, Fiona C (2018) A practical implementation of large transcriptomic data analysis to resolve cryptic species diversity problems in microbial eukaryotes. BMC Evol Biol 18:170 |
| Tekle, Yonas I; Wood, Fiona C; Katz, Laura A et al. (2017) Amoebozoans Are Secretly but Ancestrally Sexual: Evidence for Sex Genes and Potential Novel Crossover Pathways in Diverse Groups of Amoebae. Genome Biol Evol 9:375-387 |
| Wood, Fiona C; Heidari, Alireza; Tekle, Yonas I (2017) Genetic Evidence for Sexuality in Cochliopodium (Amoebozoa). J Hered 108:769-779 |
| Tekle, Yonas I; Wood, Fiona C (2017) Longamoebia is not monophyletic: Phylogenomic and cytoskeleton analyses provide novel and well-resolved relationships of amoebozoan subclades. Mol Phylogenet Evol 114:249-260 |
