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Differential expression of lumican and fibromodulin regulate collagen fibrillogenesis in developing mouse tendons.

Ezura Y, Chakravarti S, Oldberg A, Chervoneva I, Birk DE - J. Cell Biol. (2000)

Bottom Line: With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process.The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions.These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.

ABSTRACT
Collagen fibrillogenesis is finely regulated during development of tissue-specific extracellular matrices. The role(s) of a leucine-rich repeat protein subfamily in the regulation of fibrillogenesis during tendon development were defined. Lumican-, fibromodulin-, and double-deficient mice demonstrated disruptions in fibrillogenesis. With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process. Electron microscopic analysis demonstrated structural abnormalities in the fibrils and alterations in the progression through different assembly steps. In lumican-deficient tendons, alterations were observed early and the mature tendon was nearly normal. Fibromodulin-deficient tendons were comparable with the lumican- in early developmental periods and acquired a severe phenotype by maturation. The double-deficient mice had a phenotype that was additive early and comparable with the fibromodulin-deficient mice at maturation. Therefore, lumican and fibromodulin both influence initial assembly of intermediates and the entry into fibril growth, while fibromodulin facilitates the progression through growth steps leading to mature fibrils. The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions. These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis.

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Related in: MedlinePlus

Expression of lumican and fibromodulin during normal tendon development. Lumican and fibromodulin expression were analyzed using semiquantitative RT-PCR. (a) Representative ethidium bromide stained gels showing PCR product bands for lumican, fibromodulin, and coamplified GAPDH bands. Three or four different batches of PCR products generated from independently prepared total RNA between postnatal day 4 and 16 or day 21 and 3 mo were applied to a single gel. (b and c) Band density was determined densitometrically and relative density was obtained by using both band density and the PCR product size ratio, lumican 656 bp, fibromodulin 418 bp, and GAPDH 289 bp. The relative density was normalized using GAPDH and plotted for (b) lumican and (c) fibromodulin.
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Figure 2: Expression of lumican and fibromodulin during normal tendon development. Lumican and fibromodulin expression were analyzed using semiquantitative RT-PCR. (a) Representative ethidium bromide stained gels showing PCR product bands for lumican, fibromodulin, and coamplified GAPDH bands. Three or four different batches of PCR products generated from independently prepared total RNA between postnatal day 4 and 16 or day 21 and 3 mo were applied to a single gel. (b and c) Band density was determined densitometrically and relative density was obtained by using both band density and the PCR product size ratio, lumican 656 bp, fibromodulin 418 bp, and GAPDH 289 bp. The relative density was normalized using GAPDH and plotted for (b) lumican and (c) fibromodulin.

Mentions: The leucine-rich repeat proteins have been implicated in regulating fibrillogenesis, and we propose that they are involved in regulating the multiple steps observed in tendon fibril formation. Therefore, the temporal expression patterns of lumican and fibromodulin were analyzed during tendon development. Semiquantitative RT-PCR was used to analyze expression patterns for multiple independent samples from 2-d postnatal to adult (Fig. 2). Analysis demonstrated that each proteoglycan had peak expression during early stages from 2 to 14 d. Lumican expression peaked earliest at ∼8 d, and then decreased dramatically. Fibromodulin expression peaked at 14 d and decreased slightly to 1-mo postnatal, followed by a dramatic decrease in the adult expression levels.


Differential expression of lumican and fibromodulin regulate collagen fibrillogenesis in developing mouse tendons.

Ezura Y, Chakravarti S, Oldberg A, Chervoneva I, Birk DE - J. Cell Biol. (2000)

Expression of lumican and fibromodulin during normal tendon development. Lumican and fibromodulin expression were analyzed using semiquantitative RT-PCR. (a) Representative ethidium bromide stained gels showing PCR product bands for lumican, fibromodulin, and coamplified GAPDH bands. Three or four different batches of PCR products generated from independently prepared total RNA between postnatal day 4 and 16 or day 21 and 3 mo were applied to a single gel. (b and c) Band density was determined densitometrically and relative density was obtained by using both band density and the PCR product size ratio, lumican 656 bp, fibromodulin 418 bp, and GAPDH 289 bp. The relative density was normalized using GAPDH and plotted for (b) lumican and (c) fibromodulin.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169450&req=5

Figure 2: Expression of lumican and fibromodulin during normal tendon development. Lumican and fibromodulin expression were analyzed using semiquantitative RT-PCR. (a) Representative ethidium bromide stained gels showing PCR product bands for lumican, fibromodulin, and coamplified GAPDH bands. Three or four different batches of PCR products generated from independently prepared total RNA between postnatal day 4 and 16 or day 21 and 3 mo were applied to a single gel. (b and c) Band density was determined densitometrically and relative density was obtained by using both band density and the PCR product size ratio, lumican 656 bp, fibromodulin 418 bp, and GAPDH 289 bp. The relative density was normalized using GAPDH and plotted for (b) lumican and (c) fibromodulin.
Mentions: The leucine-rich repeat proteins have been implicated in regulating fibrillogenesis, and we propose that they are involved in regulating the multiple steps observed in tendon fibril formation. Therefore, the temporal expression patterns of lumican and fibromodulin were analyzed during tendon development. Semiquantitative RT-PCR was used to analyze expression patterns for multiple independent samples from 2-d postnatal to adult (Fig. 2). Analysis demonstrated that each proteoglycan had peak expression during early stages from 2 to 14 d. Lumican expression peaked earliest at ∼8 d, and then decreased dramatically. Fibromodulin expression peaked at 14 d and decreased slightly to 1-mo postnatal, followed by a dramatic decrease in the adult expression levels.

Bottom Line: With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process.The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions.These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.

ABSTRACT
Collagen fibrillogenesis is finely regulated during development of tissue-specific extracellular matrices. The role(s) of a leucine-rich repeat protein subfamily in the regulation of fibrillogenesis during tendon development were defined. Lumican-, fibromodulin-, and double-deficient mice demonstrated disruptions in fibrillogenesis. With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process. Electron microscopic analysis demonstrated structural abnormalities in the fibrils and alterations in the progression through different assembly steps. In lumican-deficient tendons, alterations were observed early and the mature tendon was nearly normal. Fibromodulin-deficient tendons were comparable with the lumican- in early developmental periods and acquired a severe phenotype by maturation. The double-deficient mice had a phenotype that was additive early and comparable with the fibromodulin-deficient mice at maturation. Therefore, lumican and fibromodulin both influence initial assembly of intermediates and the entry into fibril growth, while fibromodulin facilitates the progression through growth steps leading to mature fibrils. The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions. These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis.

Show MeSH
Related in: MedlinePlus