Breaking News
December 17, 2018 - In-school nutrition programs among students limit increases in BMI, finds study
December 17, 2018 - Risk for Hospitalization for Heart Failure Greater With Diabetes
December 17, 2018 - Food assistance may help older adults adhere to diabetes meds
December 17, 2018 - Supporting a family’s goals during a difficult pregnancy
December 17, 2018 - Neurons with Good Housekeeping Are Protected from Alzheimer’s
December 17, 2018 - CTF along with NTAP and Sage announce first-ever open data portal for neurofibromatosis
December 17, 2018 - Intimacy: The Elusive Fountain of Youth?
December 17, 2018 - Will saliva translate to a real diagnostic tool?
December 17, 2018 - DFG establishes nine new Research Units and one new Clinical Research Unit
December 17, 2018 - Assisted living’s breakneck growth leaves patient safety behind
December 17, 2018 - America’s teens report dramatic increase in their use of vaping devices in just one year
December 17, 2018 - Enlarged heart linked to a higher risk of dementia
December 17, 2018 - Prostate cancer detection using MRI now first-line investigation tool
December 17, 2018 - Loughborough academics part of new project investigating effectiveness of personalized breast cancer screening
December 17, 2018 - Adolescents who use cognitive reappraisal had better metabolic measures, shows study
December 17, 2018 - Probiotics may offer therapeutic benefits for biopolar patients
December 17, 2018 - Stealth BioTherapeutics Granted Fast Track Designation for Elamipretide for the Treatment of Dry Age-Related Macular Degeneration with Geographic Atrophy
December 17, 2018 - Studies reveal role of red meat in gut bacteria, heart disease development
December 17, 2018 - Eisai enters into agreement with Eurofarma for its anti-obesity agent lorcaserin
December 17, 2018 - Researchers use brain connectome to reassess neuroimaging findings of Alzheimer’s disease
December 17, 2018 - “Miracle” baby survives Ebola in Congo and rapid a new Ebola detection device
December 17, 2018 - Mechanisms behind neonatal diabetes uncovered
December 17, 2018 - AHF urges the WHO to expedite approval process for vaccine effective against Ebola
December 17, 2018 - Study finds misuse of benzodiazepines to be highest among young adults
December 17, 2018 - TGen receives PayPal grant to underwrite costs of genetic tests for children with rare disorders
December 17, 2018 - New research highlights why HIV-infected patients suffer higher rates of cancer
December 17, 2018 - Antibiotic-resistant bacteria could soon be targeted with Alzheimer’s drug
December 17, 2018 - Rutgers scientists take an important step in making diseased hearts heal themselves
December 17, 2018 - Tailored Feedback at CRC Screen Improves Lifestyle Behaviors
December 17, 2018 - Loss of two genes drives a deadly form of colorectal cancer, reveals a potential treatment
December 17, 2018 - How the Mediterranean Diet Can Help Women’s Hearts
December 17, 2018 - Sustained connections associated with symptoms of autism
December 17, 2018 - Concussion rates among young football players were higher than previously reported
December 17, 2018 - Cresco Labs granted approval to operate marijuana dispensary in Ohio
December 17, 2018 - Study provides insight into health risks facing new mothers
December 17, 2018 - AMSBIO expands Wnt signaling pathway product range to aid research
December 16, 2018 - Surgical treatment unnecessary for many prostate cancer patients
December 16, 2018 - Excess weight responsible for cancers globally finds report
December 16, 2018 - Regular sex associated with greater enjoyment of life in seniors
December 16, 2018 - Social stigma contributes to poor mental health in the autistic community
December 16, 2018 - Multidisciplinary team successfully performs complex surgery on patient suffering from enlarged skull
December 16, 2018 - Experts analyze data that can guide antidepressant discontinuation
December 16, 2018 - Menlo Therapeutics’ Successful Phase 2 Clinical Trial of Serlopitant Demonstrates Reduction of Pruritus Associated with Psoriasis
December 16, 2018 - Siblings of children with autism or ADHD are at elevated risk for both disorders
December 16, 2018 - New project aims to understand why and how metabolic disorders develop in patients
December 16, 2018 - Diets containing GM maize have no harmful effects on health or metabolism of rats
December 16, 2018 - Are doctors and teachers confusing immaturity and attention deficit?
December 16, 2018 - Hearing loss linked with increased risk for premature death
December 16, 2018 - Chromatrap buffer reagents for lysing cells offer many benefits
December 16, 2018 - Young Breast Cancer Patients Face Higher Risk for Osteoporosis
December 16, 2018 - 3-D printing offers helping hand to people with arthritis
December 16, 2018 - Community Health Choice helps manage complex and chronic care conditions
December 16, 2018 - Regular trips out could dramatically reduce depression in older age
December 16, 2018 - CWRU to use VivaLNK’s Vital Scout device for stress study in student athletes
December 16, 2018 - ‘Easy Way Out’? Stigma May Keep Many From Weight Loss Surgery
December 16, 2018 - Gout drug may protect against chronic kidney disease
December 16, 2018 - Talking about memories enhances the wellbeing of older and younger people
December 16, 2018 - Occupational exposure to pesticides increases risk for cardiovascular disease among Latinos
December 16, 2018 - A biomarker in the brain’s circulation system may be Alzheimer’s earliest warning
December 16, 2018 - Magnesium may play important role in optimizing vitamin D levels, study shows
December 16, 2018 - The effect of probiotics on intestinal flora of premature babies
December 16, 2018 - Parents spend more time talking with kids about mechanics of using mobile devices
December 16, 2018 - Biohaven Announces Positive Results from Ongoing Rimegepant Long-Term Safety Study
December 16, 2018 - Arterial stiffness may predict dementia risk
December 16, 2018 - Study explores link between work stress and increased cancer risk
December 16, 2018 - Sex work criminalization linked to incidences of violence finds study
December 16, 2018 - Johns Hopkins researchers discover swarming behavior in fish-dwelling parasite
December 16, 2018 - Schistosomiasis prevention and treatment could help control HIV
December 16, 2018 - Early postpartum opioids linked with persistent usage
December 16, 2018 - Johns Hopkins researchers identify molecular causes of necrotizing enterocolitis in preemies
December 16, 2018 - Advanced illumination expands capabilities of light-sheet microscopy
December 16, 2018 - Alzheimer’s could possibly be spread via contaminated neurosurgery
December 16, 2018 - Unraveling the complexity of cancer biology can prompt new avenues for drug development
December 16, 2018 - Inflammatory Bowel Disease, Prostate Cancer Linked
December 16, 2018 - Cannabis youth prevention strategy should target mental wellbeing
December 15, 2018 - Recent developments and challenges in hMAT inhibitors
December 15, 2018 - Sewage bacteria found lurking in Hudson River sediments
December 15, 2018 - CDC selects UMass Amherst biostatistician model that helps predict influenza outbreaks
December 15, 2018 - Researchers reveal brain mechanism that drives itch-evoked scratching behavior
December 15, 2018 - New computer model helps predict course of the disease in prostate cancer patients
Absence of a transcription factor halts tooth development in mid-stride

Absence of a transcription factor halts tooth development in mid-stride

image_pdfDownload PDFimage_print
Absence of a transcription factor halts tooth development in mid-stride
From left: Amjad Javed, Ph.D., and Haiyan Chen. Credit: University of Alabama at Birmingham

Amjad Javed, Ph.D., and University of Alabama at Birmingham colleagues have found a key role in tooth development for the transcription factor Specificity protein 7, or Sp7.

Using an animal model, the UAB researchers found that a lack of Sp7 interrupts the maturation of two types of specialized cells that help create teeth. Such basic knowledge about the development of teeth or bones adds to understanding of craniofacial abnormalities, which are among the most common birth defects in humans.

Transcription factors are proteins that interact with DNA to turn genes on or off. In embryos, they guide differentiation from the single fertilized egg into all cells that form the different tissues and structures of the body. One of those complex structures is the tooth.

The teeth of mammals develop during embryonic growth, though they erupt only after birth. In research published in the Journal of Bone and Mineral Research, Javed, a professor in the UAB School of Dentistry’s Department of Oral and Maxillofacial Surgery, used a mouse model with mutations in both copies of the gene for Sp7.

It was previously known that Sp7 is required for bone development. Embryos with a double mutation in Sp7 completely lack mineralized bone. In humans, mutation of the Sp7 gene causes osteogenesis imperfecta, a condition that affects the development of bones and craniofacial structures. However, the role of Sp7 in embryonic tooth development was unknown.

Through study of mice lacking Sp7, Javed and colleagues found that initial tooth morphogenesis was normal, even though the animals lacked mineralized tooth sockets. However, tooth development did not continue—the animals failed to produce normal dentin, the hard tissue that forms the bulk of the tooth, and they failed to produce normal enamel, the super-hard matrix layer that covers the tooth. This was due to reduced proliferation, maturation and polarization of the tooth-forming cells called odontoblasts and ameloblasts.

Odontoblasts line up side by side inside the developing tooth to form a sheet of columnar cells that deposit dentin. Similarly, ameloblasts line up side by side in a sheet outside the developing tooth to lay down enamel.

Without Sp7, the animals had small, misshapen teeth, and the odontoblasts and ameloblasts failed to mature beyond the pre-odontoblast and pre-ameloblast stage, as measured by absence of mature cell markers for those two types of cells. The odontoblasts and ameloblasts were fewer in number and showed disorganized alignments.

The researchers found that Sp7 in normal mice was expressed only in the dental mesenchymal tissue that gives rise to odontoblasts; it was not expressed in the oral epithelium that gives rise to ameloblasts. Since it is known that 13 different members of the fibroblast growth factor, or Fgf, family act as signaling proteins between the two different tissues—dental mesenchyme and oral epithelium—during murine tooth development, Javed and colleagues looked for changes in Fgf ligands in the mice lacking Sp7.

They found that the Fgf3 and Fgf8 ligands, which are abundant in normal tooth development, were remarkably absent in incisor and molar teeth of the animals lacking Sp7. This indicated that a disrupted cross-signaling between mesenchyme and epithelium was the reason for the failed maturation of ameloblasts. Furthermore, they found that the Sp7 transcription factor directly controlled gene expression of the Fgf ligands.

Altogether, the UAB researchers concluded that Sp7 is obligatory for differentiation of ameloblasts and odontoblasts, but not for the initial tooth morphogenesis.


Explore further:
Beta-catenin molecule is required for tooth root formation

More information:
Ji-Myung Bae et al. Specificity Protein 7 Is Required for Proliferation and Differentiation of Ameloblasts and Odontoblasts, Journal of Bone and Mineral Research (2018). DOI: 10.1002/jbmr.3401

Journal reference:
Journal of Bone and Mineral Research

Provided by:
University of Alabama at Birmingham

Tagged with:

About author

Related Articles