Navigation Links
The developmental genetics of space and time

Albert Erives, associate professor in the University of Iowa Department of Biology, and his graduate student, Justin Crocker, currently a postdoctoral researcher at the Howard Hughes Medical Institute (HHMI) Janelia Farm Research Campus, have conducted a study that reveals important and useful insights into how and why developmental genes often take inputs from two independent "morphogen concentration gradients."

The study appears in the Genomes & Developmental Control section of the online June 1 issue of the journal Developmental Biology. The complete paper can be found at:

Understanding the concept of morphogen gradientsthe mechanism by which a signal from one part of a developing embryo can influence the location and other variables of surrounding cellsis important to developmental biology, gene regulation, evolution, and human health.

Morphogen gradients subdivide a field of cells into territories characterized by distinct cell fate potentials and allow cells to "know" their position within a developing embryonic tissue and to differentiate appropriately. In order to function, such systems require a genetic mechanism to encode a spectrum of responses at different target genes.

This genetic mechanism takes the form of transcriptional enhancers, which are DNA sequences that display a cryptic code of transcription factor (TF) binding sites. During development and/or environmental perturbation, these enhancers serve as assembly scaffolds for TF protein complexes that orchestrate differential gene expression.

However, enhancers targeted by morphogen signaling may drive temporally inappropriate expression because morphogen gradients also provide temporal cues. That is, the morphogenic gradient builds up and decays over a specific window of developmental time.

Using the powerful Drosophila (fruit fly) genetic system, which includes diverse species with fully sequenced genomes, the Erives Lab identified a case of spatial and temporal conflict in the regulation of the ventral neurons defective (vnd) gene, which must be precisely regulated in order for the fly's nervous system to be properly specified. The vnd gene is induced by a concentration gradient of a key embryonic factor (dorsal/NFkB) that patterns the dorsal/ventral (D/V) axis of the embryo. In particular, the vnd gene plays a critical role in specifying distinct D/V neural columnar fates of the ectodermal compartments by encoding a repressor of additional regulators.

The role of vnd in this regulatory hierarchy requires early temporal expression, which is characteristic of low-threshold responses, but its specification of ventral neurogenic ectoderm demands a relatively high-threshold response to the morphogen.

The study shows that the vnd gene's Neurogenic Ectoderm Enhancer (NEE) takes additional input from a complementary gradient of the Dpp morphogen via a highly-conserved Schnurri/Mad/Medea silencer element (SSE), which is integral to its NEE module. In this regard, the NEE at vnd is unlike NEEs at other genetic loci, which are not involved in the neural specification circuit and have no resident SSE. They also show that an SSE could be added to a single-input NEE and cause spatial restriction of its activity. These results show how requirements for conflicting temporal and spatial responses to one morphogen gradient can be solved by additional inputs from complementary morphogen gradients.

The Erives Lab at the UI's Department of Biology studies the structure, function, and evolution of enhancers within the context of gene regulatory circuits underlying the evolution and development of animals by using molecular, genetic, and evolutionary genomic approaches. Within these areas, the Erives Lab has published several landmark papers notable for demonstrating how whole genome sequences can be used to accelerate biological research on outstanding questions in biology.


Contact: Gary Galluzzo
University of Iowa

Related medicine news :

1. Study looks at how states decide which child receives early intervention for developmental problems
2. Pitt research sheds new light on virus associated with developmental delays and deafness
3. Flame retardants linked to neurodevelopmental delays in children
4. Improved Developmental Screening Urged for Hispanic Kids
5. Diagnosis often missed for Hispanic children with developmental delay, autism
6. Dental Woes Abound for Developmentally Disabled: Study
7. Group B streptococcal meningitis has long-term effects on childrens developmental outcomes
8. Developmental Woes Common in Siblings of Children With Autism
9. Champion of Genetics funding to Ottawa researcher
10. Ottawa researcher named 2013 Champion of Genetics
11. Johns Hopkins experts to present genetics advances at international meeting this weekend
Post Your Comments:
(Date:11/27/2015)... (PRWEB) , ... November 27, 2015 , ... ... the largest, most successful and prominent nonprofit healthcare organizations in the country. They ... involvement with various organizations, and helped advance the healthcare industry as a whole ...
(Date:11/26/2015)... ... November 26, 2015 , ... Patients at ... Michigan, have come together on Thanksgiving Day to share the things that they ... on the Serenity Point YouTube channel, patients displayed what they wrote on index ...
(Date:11/26/2015)... ... November 26, 2015 , ... The Catalent Applied Drug ... need to integrate dose form selection in early phase drug development. The first ... supporting and bringing together the UK’s emerging life sciences companies, corporate partners, and ...
(Date:11/26/2015)... CA (PRWEB) , ... November 26, 2015 , ... ... a new set of retro-fused, self-animating trailer titles with ProTrailer: Vintage. This newly ... options. These classically-influenced trailer titles work with any font, giving users limitless opportunities ...
(Date:11/25/2015)... ... November 25, 2015 , ... As part of ... Empowerment ™ attracts volunteers together who want to combine talents and resources to ... stakeholders in the process. The non-profit launched its first major fundraiser on November ...
Breaking Medicine News(10 mins):
(Date:11/25/2015)... -- The total global healthcare industry is expected to grow at ... America has the highest projected growth at 12.7%, ... ), is second with growth projected at 11.5%. ... expenditure. In 2013-2014, total government funded healthcare was nearly 68%. ... 41.2% in 2013-2014. In real terms, out of pocket expenditure ...
(Date:11/25/2015)...  The American Academy of Pediatrics (AAP), American ... March of Dimes cheered today,s signature into law ... of 2015 (S.799), which takes much-needed strides ... to drugs, such as opioids, and to improve ... organizations have worked together leading advocacy efforts for ...
(Date:11/25/2015)... Nov. 25, 2015 AAIPharma Services Corp./Cambridge ... of at least $15.8  Million to expand its ... NC . The expansion will provide additional ... the growing demands of the pharmaceutical and biotechnology ... expansion will provide up to 40,000 square feet ...
Breaking Medicine Technology: