Related Experiment Video
Updated: May 26, 2026
11:48
Detection of Alternative Splicing During Epithelial-Mesenchymal Transition
Published on: October 9, 2014
Porcine Amelogenin : Alternative Splicing, Proteolytic Processing, Protein - Protein Interactions, and Possible
1Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan Dental Research Lab, 1210 Eisenhower Place, Ann Arbor, MI 48108, USA.
Journal of Oral Biosciences
|December 28, 2011
Summary
Amelogenin isoforms and their breakdown products are crucial for tooth enamel development. Matrix metalloproteinase 20 (Mmp20) processing generates distinct amelogenin fragments with specific functions, influencing enamel mineralization and crystal growth.
Area of Science:
- Biochemistry
- Developmental Biology
- Materials Science
Background:
- Amelogenin is the primary protein in developing tooth enamel, essential for its structure.
- Over 80% of enamel protein consists of amelogenin isoforms and their breakdown products.
- Understanding amelogenin processing is key to comprehending enamel formation.
Purpose of the Study:
- To isolate and characterize secreted amelogenin isoforms from porcine enamel.
- To investigate the cleavage of amelogenins by matrix metalloproteinase 20 (Mmp20).
- To explore the functional roles of amelogenin fragments and their interactions during enamel development.
Main Methods:
- Isolation and characterization of four amelogenin isoforms (P190, P173, P132, LRAP) from developing porcine enamel.
- Analysis of P173 cleavage by Mmp20 to identify resulting fragments (P162, P148, P62/P63, TRAP).
- Far-Western blotting to study protein-protein interactions between amelogenin isoforms and cleavage products.
Main Results:
- Identified four secreted amelogenin isoforms: P190, P173, P132, and LRAP.
- Mmp20 cleaves P173 into smaller fragments, including P148, the most abundant protein, and LRAP.
- Larger amelogenins interact with each other, while smaller fragments (TRAP, LRAP) do not. Amelogenin interactions with enamelin depend on enamelin deglycosylation.
Conclusions:
- Mmp20-mediated processing of amelogenins generates fragments with distinct functions crucial for enamel mineralization.
- Specific protein-protein interactions among amelogenins regulate their function during enamel development.
- The progressive replacement of amelogenin by mineral, facilitated by Mmp20, allows enamel crystals to thicken and widen.
Related Concept Videos
01:32RNA Splicing
Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
02:18Alternative RNA Splicing
Alternative RNA splicing is the regulated splicing of exons and introns to produce different mature mRNAs from a single pre-mRNA. Unlike in constitutive splicing where a single gene produces a single type of mRNA, alternative splicing allows an organism to produce multiple proteins from a single gene and plays an important role in protein diversity.
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
02:01Pre-mRNA Processing
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
03:03Amyloid Fibrils
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
01:36What is Gene Expression?
A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised of nucleotides and proteins are comprised of amino acids, a mediator is required to convert the information encoded in DNA into proteins. This mediator is the messenger RNA (mRNA). mRNA copies the blueprint from DNA by a process called transcription. In eukaryotes, transcription occurs in the nucleus by complementary base-pairing with the DNA template. The mRNA is then processed and...
01:57Protein Complexes with Interchangeable Parts
Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...