Fibulin-2 is dispensable for mouse development and elastic fiber formation.
Fibulin-2 is an extracellular matrix protein belonging to the five-member fibulin family, of which two members have been shown to play essential roles in elastic fiber formation during development. Fibulin-2 interacts with two major constituents of elastic fibers, tropoelastin and fibrillin-1, in vitro and localizes to elastic fibers in many tissues in vivo. The protein is prominently expressed during morphogenesis of the heart and aortic arch vessels and at early stages of cartilage development. To examine its role in vivo, we generated mice that do not express the fibulin-2 gene (Fbln2) through homologous recombination of embryonic stem cells. Unexpectedly, the fibulin-2-null mice were viable and fertile and did not display gross and anatomical abnormalities. Histological and ultrastructural analyses revealed that elastic fibers assembled normally in the absence of fibulin-2. No compensatory up-regulation of mRNAs for other fibulin members was detected in the aorta and skin tissue. However, in the fibulin-2 null aortae, fibulin-1 immunostaining was increased in the inner elastic lamina, where fibulin-2 preferentially localizes. The results demonstrate that fibulin-2 is not required for mouse development and elastic fiber formation and suggest possible functional redundancy between fibulin-1 and fibulin-2.
Sicot
Francois-Xavier
FX
Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA 19107, USA.
Tsuda
Takeshi
T
Markova
Dessislava
D
Klement
John F
JF
Arita
Machiko
M
Zhang
Rui-Zhu
RZ
Pan
Te-Cheng
TC
Mecham
Robert P
RP
Birk
David E
DE
Chu
Mon-Li
ML
D000818:Animals; D001011:Aorta / Q000737:chemistry / Q000166:cytology; D002135:Calcium-Binding Proteins / Q000032:analysis / Q000172:deficiency / Q000502:physiology*; D004547:Elastic Tissue / Q000254:growth & development*; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000172:deficiency / Q000502:physiology*; D048788:Growth and Development; D051379:Mice; D018345:Mice, Knockout; D010641:Phenotype
D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; C084612:fibulin 2