Worm Development

Introduction

C.Elegans

Initially used in the 1960's by Sydney Brenner to study the genetics of development and neurobiology. Early embryological studies of the nematode worm (roundworm) Caenorhabditis elegans (C.Elegans, so called because of its "elegant" curving movement) characterized the fate of each and every cell in the worm through all stages of development. This worm was the first to have its entire genome sequenced and also used recently in space experiments (see below).

The USA space shuttle Atlantis in November 2009 launched Caenorhabditis elegans into space as part of an experiment to study RNA interference and protein phosphorylation in a space environment.

"RNA interference and protein phosphorylation in space environment using the nematode Caenorhabditis elegans (CERISE) is an experiment that addresses two scientific objectives. The first is to evaluate the effect of microgravity on ribonucleic acid (RNA) interference. The second is to study how the space environment effects protein phosphorylation (addition of a phosphate molecule) and signal transduction in the muscle fibers of gene knock-downed Caenorhabditis elegans."

Links: original page

Some Recent Findings

Basic Caenorhabditis elegans Methods: Synchronization and Observation "Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has since been used extensively as a model organism (1). C. elegans possesses key attributes such as simplicity, transparency and short life cycle that have made it a suitable experimental system for fundamental biological studies for many years (2). ...Because of its transparency, C. elegans structures can be distinguished under the microscope using Differential Interference Contrast microscopy, also known as Nomarski microscopy. The use of a fluorescent DNA binder, DAPI (4',6-diamidino-2-phenylindole), for instance, can lead to the specific identification and localization of individual cells, as well as subcellular structures/defects associated to them." Small RNAs and temporal control in Caenorhabditis elegans. "Developmental timing studies in C. elegans led to the landmark discovery of miRNAs and continue to enhance our understanding of the regulation and activity of these small regulatory molecules. Current views of the heterochronic gene pathway are summarized here, with a focus on the ways in which miRNAs contribute to temporal control and how miRNAs themselves are regulated. Finally, the conservation of heterochronic genes and their functions in timing, as well as their related roles in stem cells and cancer, are highlighted."

Adult Anatomy

Adult Hermaphrodite Gonad

Adult hermaphrodite gonad arm - A drawing representation of an adult hermaphrodite gonad arm. The progression of germ cell proliferation and meiosis are indicated by the arrows starting from the distal tip region of the gonad arm.

Male Development

The features that differentiate the C. elegans male from the hermaphrodite arise during postembryonic development.

RNA interference

The two researchers, Andrew Z. Fire and Craig C. Mello, were investigating how gene expression is regulated in C. elegans and identified the novel regulation method of RNA interference (RNAi), gene silencing by double-stranded RNA. This discovery was awarded the 2006 Nobel Prize in Physiology or Medicine.

Links: 2006 Nobel Press Release

Embryonic Cell Lineages

The overview diagram above shows the fate of each individual cell in the developing c. elegans.

• Zygote (P0 cell) divides into two daughter cells (AB and P1 cells).
• These two daughter cells then divide into the next generation.
• the "X" indicates cells that die by apoptosis during development.

Note the above image is not at a readable resolution, to view see large readable version (10,389 × 1,336 pixels). Embryonic cell lineage developed by J .E. Sulston, E. Schierenberg, J. G. White, J. N. Thomson.

Links: Apoptosis | Worm Atlas - Cell Lineages

Gastrointestinal Tract

The worm digestive tract consists of a pharynx, intestine, and rectum and contains only about 100 cells. Development is regulated by similar transcription factors found for other species (FoxA and GATA factors).

• FoxA - pharynx and rectum
• GATA - intestine

References

Reviews

WormBook - a comprehensive, open-access collection of original, peer-reviewed chapters covering topics related to the biology of Caenorhabditis elegans and other nematodes.

• Asymmetric cell division and axis formation in the embryo
• Embryological variation during nematode development

Search Pubmed

July 2010 "c elegans Development" All (5126) Review (898) Free Full Text (2363)

Search Pubmed: Worm Development | Caenorhabditis elegans Development | c elegans Development

External Links

External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name.

• WormBook open-access collection of chapters covering topics related to the biology of Caenorhabditis elegans (C. elegans) and other nematodes.
• Caenorhabditis Genome Sequencing Projects
• Caenorhabditis elegans WWW Server
• The Hall lab - aim to serve the C. elegans community by creating a digital database of TEM images & wild type tissues- an Atlas of worm anatomy.

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What Links Here?

Cite this page:

Hill, M.A. (2013) Worm Development. Retrieved June 19, 2013, from http://php.med.unsw.edu.au/embryology/index.php?title=Worm_Development

Dr Mark Hill 2013, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G