Tissue-specific and ubiquitous expression of fibrinogen gamma-chain mRNA.
Fibrinogen gamma-chains are derived from differential mRNA splicing resulting in polypeptide that differ in their carboxyterminal sequences as well as tissue distribution. We examined the expression of the rat fibrinogen gamma-chain mRNAs to determine the nature of the differential tissue expression of the gamma-fibrinogens. Here we demonstrate that the expression of the rat gamma B mRNA is tissue-specific. Northern blot analysis indicated that gamma A mRNA was expressed in liver, lung, brain and marrow, while the alternatively spliced gamma B mRNA was expressed only in liver. Three distinct full-length species of gamma B mRNA were identified in liver, indicative of multiple sites for polyadenylation that is suggestive of regulation at the level of 3' RNA processing. The restricted expression of gamma B mRNA in liver was contrasted by the ubiquitous expression of the gamma-chain promoter in brain and lung tissues that are not known for production of plasma coagulation proteins. The results of in situ hybridization showed that only gamma A mRNA was found in lung, localized to bronchiolar epithelial cells and chondrocytes but not smooth muscle or endothelial cells. Tissue-specific regulation of the gamma-chain gene results in compartmentalization of gamma B-fibrinogen to the circulation.
Haidaris
P J
PJ
University of Rochester School of Medicine and Dentistry, Department of Medicine, Rochester, NY 14642.
Courtney
M A
MA
D000818:Animals; D001921:Brain / Q000378:metabolism; D005340:Fibrinogen / Q000096:biosynthesis / Q000235:genetics*; D005786:Gene Expression Regulation; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D009928:Organ Specificity; D012326:RNA Splicing; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity
D012333:RNA, Messenger; C027539:fibrinopeptides gamma; D005340:Fibrinogen