Biomaterial Database

Developmental changes in isoactin expression in rat aortic smooth muscle cells in vivo. Relationship between growth and cytodifferentiation. 1986

G K Owens, and M M Thompson

There is an inverse relationship between cellular proliferation and smooth muscle alpha-isoactin expression in cultured vascular smooth muscle cells (SMCs) (Owens, G.K., Loeb, A., Gordon, D., and Thompson, M.M. (1986) J. Cell Biol. 102, 343-352). In the present studies, changes in isoactin expression were studied during developmental growth of rat aortic SMCs (ages 1-180 days) to better understand interrelationships between growth and cytodifferentiation in these cells in vivo. Actin expression (i.e. content and synthesis) was evaluated by one- and two-dimensional gel electrophoresis and using isoactin-specific antibodies. The major actin present in cells from newborn rats was nonmuscle beta-actin (56% of total actin), whereas cells from adult animals contained principally smooth muscle alpha-actin (Sm-alpha-actin) (76% of total actin). Increases in Sm-alpha-actin content with increasing age were due, in part, to an increase in Sm-alpha-actin synthesis. However, in SMCs from 90- and 180-day-old rats, the fractional content of Sm-alpha-actin exceeded its fractional synthesis at a time when total Sm-alpha-actin content was increasing. This suggests that Sm-alpha-actin turns over more slowly in mature animals. Decreases in the frequency of SMCs undergoing DNA synthesis with age could not account for increases in Sm-alpha-actin expression with age. However, combined immunocytological and [3H]thymidine autoradiographic studies demonstrated that nearly 50% of the medial derived cells from newborn rat aortas did not show detectable staining with a monoclonal antibody to smooth muscle-specific isoactins, and the replicative frequency was much higher in these cells than in cells that contained Sm-alpha-isoactins. Taken together, the results of the present studies and previous studies in cultured SMCs support the hypothesis that cessation of proliferation during development is associated with the induction of Sm-alpha-actin expression, but that factors other than cellular growth state play an important role in determining the level of Sm-alpha-actin expression in fully differentiated SMCs.

UI	MeSH Term	Description	Entries
D007525	Isoelectric Focusing	Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.	Electrofocusing,Focusing, Isoelectric
D009131	Muscle, Smooth, Vascular	The nonstriated involuntary muscle tissue of blood vessels.	Vascular Smooth Muscle,Muscle, Vascular Smooth,Muscles, Vascular Smooth,Smooth Muscle, Vascular,Smooth Muscles, Vascular,Vascular Smooth Muscles
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D002455	Cell Division	The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.	M Phase,Cell Division Phase,Cell Divisions,Division Phase, Cell,Division, Cell,Divisions, Cell,M Phases,Phase, Cell Division,Phase, M,Phases, M
D004261	DNA Replication	The process by which a DNA molecule is duplicated.	Autonomous Replication,Replication, Autonomous,Autonomous Replications,DNA Replications,Replication, DNA,Replications, Autonomous,Replications, DNA
D000199	Actins	Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.	F-Actin,G-Actin,Actin,Isoactin,N-Actin,alpha-Actin,alpha-Isoactin,beta-Actin,gamma-Actin,F Actin,G Actin,N Actin,alpha Actin,alpha Isoactin,beta Actin,gamma Actin
D000367	Age Factors	Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.	Age Reporting,Age Factor,Factor, Age,Factors, Age
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001013	Aorta, Thoracic	The portion of the descending aorta proceeding from the arch of the aorta and extending to the DIAPHRAGM, eventually connecting to the ABDOMINAL AORTA.	Aorta, Ascending,Aorta, Descending,Aortic Arch,Aortic Root,Arch of the Aorta,Descending Aorta,Sinotubular Junction,Ascending Aorta,Thoracic Aorta,Aortic Roots,Arch, Aortic,Ascending Aortas,Junction, Sinotubular,Root, Aortic,Sinotubular Junctions
D013936	Thymidine	A nucleoside in which THYMINE is linked to DEOXYRIBOSE.	2'-Deoxythymidine,Deoxythymidine,2' Deoxythymidine