Biomaterial Database

Human fibroblast tropomyosin isoforms: characterization of cDNA clones and analysis of tropomyosin isoform expression in human tissues and in normal and transformed cells. 1993

R E Novy, and J L Lin, and C S Lin, and J J Lin

Department of Biological Sciences, University of Iowa, Iowa City 52242-1324.

A tropomyosin-specific oligonucleotide probe (REN29) designed to hybridize to all known human tropomyosin isoforms was used to study tropomyosin mRNA levels in normal and transformed human cells. At least four different sizes of RNAs were detected in normal human fibroblast KD cells by Northern blot analysis. The major bands of 1.1 kb RNA for hTM1 and 3.0 kb RNA for hTM4 were decreased substantially in various transformed cell lines. One of the minor RNA bands (2.0 kb for hTM2 and hTM3) appeared to be absent in a human pancreatic carcinoma cell line. The level of the other minor RNA band (2.5 kb for hTM5) was found to be unchanged or slightly decreased in transformed cells. This differential expression of tropomyosin isoforms at the RNA level was not totally in agreement with the difference in the protein amounts found in normal and transformed cells, suggesting that translational control may also play an important role in the expression of some tropomyosin isoforms. The REN29 probe was further used to screen lambda gt10 and lambda gt11 cDNA libraries, which were constructed from poly(A)+ RNAs of human fibroblast cell lines HuT-14 and WI-38, respectively. In addition to cDNA clones encoding known isoforms, we obtained three classes of new cDNA clones that encode two low M(r) isoforms (hTM5a and hTM5b), and a high M(r) isoform (hTMsm alpha). Sequence comparison revealed that hTM5a and hTM5b are alternatively spliced products derived from the same gene that encodes hTM2 and hTM3. Northern blot analysis and amino acid sequence comparison suggested that the hTMsm alpha represents a smooth muscle tropomyosin which is also expressed in human fibroblasts. The exon specific for, and common to, hTM5a and hTM5b was found to be highly expressed in small intestine. However, there was no detectable expression of this exon in stomach and skeletal muscle. The difference in tissue-specific expression suggests that different isoforms may perform distinct functions in different tissues.

UI	MeSH Term	Description	Entries
D007421	Intestine, Small	The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.	Small Intestine,Intestines, Small,Small Intestines
D007536	Isomerism	The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Isomerisms
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D010190	Pancreatic Neoplasms	Tumors or cancer of the PANCREAS. Depending on the types of ISLET CELLS present in the tumors, various hormones can be secreted: GLUCAGON from PANCREATIC ALPHA CELLS; INSULIN from PANCREATIC BETA CELLS; and SOMATOSTATIN from the SOMATOSTATIN-SECRETING CELLS. Most are malignant except the insulin-producing tumors (INSULINOMA).	Cancer of Pancreas,Pancreatic Cancer,Cancer of the Pancreas,Neoplasms, Pancreatic,Pancreas Cancer,Pancreas Neoplasms,Pancreatic Acinar Carcinoma,Pancreatic Carcinoma,Acinar Carcinoma, Pancreatic,Acinar Carcinomas, Pancreatic,Cancer, Pancreas,Cancer, Pancreatic,Cancers, Pancreas,Cancers, Pancreatic,Carcinoma, Pancreatic,Carcinoma, Pancreatic Acinar,Carcinomas, Pancreatic,Carcinomas, Pancreatic Acinar,Neoplasm, Pancreas,Neoplasm, Pancreatic,Neoplasms, Pancreas,Pancreas Cancers,Pancreas Neoplasm,Pancreatic Acinar Carcinomas,Pancreatic Cancers,Pancreatic Carcinomas,Pancreatic Neoplasm
D001749	Urinary Bladder Neoplasms	Tumors or cancer of the URINARY BLADDER.	Bladder Cancer,Bladder Neoplasms,Cancer of Bladder,Bladder Tumors,Cancer of the Bladder,Malignant Tumor of Urinary Bladder,Neoplasms, Bladder,Urinary Bladder Cancer,Bladder Cancers,Bladder Neoplasm,Bladder Tumor,Cancer, Bladder,Cancer, Urinary Bladder,Neoplasm, Bladder,Neoplasm, Urinary Bladder,Tumor, Bladder,Tumors, Bladder,Urinary Bladder Neoplasm
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002461	Cell Line, Transformed	Eukaryotic cell line obtained in a quiescent or stationary phase which undergoes conversion to a state of unregulated growth in culture, resembling an in vitro tumor. It occurs spontaneously or through interaction with viruses, oncogenes, radiation, or drugs/chemicals.	Transformed Cell Line,Cell Lines, Transformed,Transformed Cell Lines
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning