How to Build an Allorecognition System: A Guide for Prospective Multicellular Organisms

Grice, Laura F.; Degnan, Bernard M.

doi:10.1007/978-94-017-9642-2_19

Cited by 15 publications

(23 citation statements)

References 169 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, allorecognition molecules are often encoded by genes that are clustered in the genome, a phenomenon that supports further molecular diversification (Grice and Degnan 2015a). In A. queenslandica , the five AF genes are clustered within an 80-kb genomic locus.…”

Section: Discussionmentioning

confidence: 99%

Origin and evolution of the sponge aggregation factor gene family

et al. 2017

Self Cite

View full text Add to dashboard Cite

Although discriminating self from nonself is a cardinal animal trait, metazoan allorecognition genes do not appear to be homologous. Here, we characterize the Aggregation Factor (AF) gene family, which encodes putative allorecognition factors in the demosponge Amphimedon queenslandica, and trace its evolution across 24 sponge (Porifera) species. The AF locus in Amphimedon is comprised of a cluster of five similar genes that encode Calx-beta and Von Willebrand domains and a newly defined Wreath domain, and are highly polymorphic. Further AF variance appears to be generated through individualistic patterns of RNA editing. The AF gene family varies between poriferans, with protein sequences and domains diagnostic of the AF family being present in Amphimedon and other demosponges, but absent from other sponge classes. Within the demosponges, AFs vary widely with no two species having the same AF repertoire or domain organization. The evolution of AFs suggests that their diversification occurs via high allelism, and the continual and rapid gain, loss and shuffling of domains over evolutionary time. Given the marked differences in metazoan allorecognition genes, we propose the rapid evolution of AFs in sponges provides a model for understanding the extensive diversification of self–nonself recognition systems in the animal kingdom.

show abstract

Section: Discussionmentioning

confidence: 99%

Origin and evolution of the sponge aggregation factor gene family

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Simple multicellular organisms exhibit phenotypes based on multiple, attached cells, arising either through the aggregation of numerous unicellular individuals, or through the lack of total separation following the division of a single‐celled progenitor (Grice & Degnan, ; Herron & Nedelcu, ). The simplest multicellular phenotypes (i.e., organisms exhibiting simple multicellularity) include sheets, clusters, and chains of physically attached cells that largely remain in direct contact with the external environment and exhibit limited intercellular differentiation, communication, and resource exchange (Knoll & Hewitt, ).…”

Section: Introduction —Animals Are Trophically Uniquementioning

confidence: 99%

A trophic framework for animal origins

Mills

Canfield

2016

Geobiology

View full text Add to dashboard Cite

Metazoans emerged in a microbial world and play a unique role in the biosphere as the only complex multicellular eukaryotes capable of phagocytosis. While the bodyplan and feeding mode of the last common metazoan ancestor remain unresolved, the earliest multicellular stem-metazoans likely subsisted on picoplankton (planktonic microbes 0.2-2 μm in diameter) and dissolved organic matter (DOM), similarly to modern sponges. Once multicellular stem-metazoans emerged, they conceivably modulated both the local availability of picoplankton, which they preferentially removed from the water column for feeding, and detrital particles 2-100 μm in diameter, which they expelled and deposited into the benthos as waste products. By influencing the availability of these heterotrophic food sources, the earliest multicellular stem-metazoans would have acted as ecosystem engineers, helping create the ecological conditions under which other metazoans, namely detritivores and non-sponge suspension feeders incapable of subsisting on picoplankton and DOM, could emerge and diversify. This early style of metazoan feeding, specifically the phagocytosis of small eukaryotic prey, could have also encouraged the evolution of larger, even multicellular, eukaryotic forms less prone to metazoan consumption. Therefore, the first multicellular stem-metazoans, through their feeding, arguably helped bridge the strictly microbial food webs of the Proterozoic Eon (2.5-0.541 billion years ago) to the more macroscopic, metazoan-sustaining food webs of the Phanerozoic Eon (0.541-0 billion years ago).

show abstract

“…It is a ubiquitous feature of living organisms that is essential in a wide range of inter-and intraspecies interactions. This process generally occurs in three phases: the first step is 'detection', which involves the individual unit (cell or organism) detecting the presence of another biological entity in its environment; the second step is 'recognition', where the detected unit is identified as either 'self' or 'nonself'; and the third step is 'discrimination', where the individual unit takes some action based on the identity of the detected unit and the context of the interaction (Grice and Degnan, 2015).…”

Section: List Of Figuresmentioning

confidence: 99%

“…The presence of an allorecognition system would have been critical during a transition to multicellularity, regardless of the context of the transition. The ability to recognize and differentiate between self and nonself would help prevent interactions with 'cheaters' who may take advantage of the benefits of multicellularity without contributing to the overall fitness of the organism, or alternatively encourage interactions with genetically dissimilar individuals during sexual reproduction as a means to maintain genetic diversity (Grice and Degnan, 2015).…”

Section: List Of Figuresmentioning

confidence: 99%

Examining the role of the promoter region of het-6 in escape from heterokaryon incompatibility in Neurospora crassa

Laoye¹

View full text Add to dashboard Cite

Heterokaryon incompatibility (HI) is a form of nonself recognition that limits the formation of heterokaryons -cells that contain genetically dissimilar nuclei. HI is controlled by several het loci. One of these, het-6 is a supergene complex that encodes two tightly-linked incompatibility genes, un-24 and het-6, with allelic variants Oak Ridge (OR) and Panama (PA), and only two natural haplotypes -un-24 OR het-6 OR or un-24 PA het-6 PA . het-6 encodes a HET domain protein with no known function outside of incompatibility, whereas un-24 encodes incompatibility function and the large subunit of ribonucleotide reductase. Strains incompatible at the het-6 locus can 'escape' from HI by mutation in the het-6 gene (Type I, ~97%), or suppress HI by mutation in a transcription factor called vib-1 (Type II, ~3%). This study examined the possible role of the het-6 promoter region in the initiation of escape, by introducing an ectopic het-6 OR allele into a strain that carried a null endogenous het-6 OR allele (IB20). Self-incompatible transformants exhibited delayed escape and aberrant post-escape behavior. A vib-1 mutant allele was introduced into IB20, and the resulting strain was also transformed with the ectopic het-6 OR . Transformants displayed Type-II like phenotype, but had slower growth rates than a typical Type II strain. Finally, we constructed a plasmid containing the het-6 OR allele in which the putative VIB-1 + binding site was deleted. Transformation of IB20 with this construct generated a transformant with a Type II-like growth phenotype. This study provides insight into the process of escape.iii Acknowledgements First, I would like to thank Dr. Myron Smith, who welcomed me into his lab over four years ago, and has always been a patient teacher and provided invaluable guidance through the completion of this project. I would also like to thank my committee members,

show abstract

How to Build an Allorecognition System: A Guide for Prospective Multicellular Organisms

Cited by 15 publications

References 169 publications

Origin and evolution of the sponge aggregation factor gene family

Origin and evolution of the sponge aggregation factor gene family

A trophic framework for animal origins

Examining the role of the promoter region of het-6 in escape from heterokaryon incompatibility in Neurospora crassa

Contact Info

Product

Resources

About