Structural characterization of the rat cysteine-rich intestinal protein gene and overexpression of this LIM-only protein in transgenic mice.
Cysteine-rich intestinal protein (CRIP) has a double zinc-finger motif called the LIM domain. The most elementary member of the Group 2 LIM-only protein family, CRIP was initially identified as a developmentally regulated intestinal gene. Subsequently, it was found to be highly expressed in immune cells. The structural portion of the rat CRIP gene is comprised of five exons extending over i.8 kb, with the two zinc-finger motifs of the LIM domain being divided among the first three exons. In addition to transcriptional regulatory elements previously identified in the promoter, consensus sequences for AP-1, AP2, Sp-1, and a glucocorticoid response element are located within the first intron. We have developed a line of transgenic mice that overexpress the rat CRIP gene with an expression profile that mirrors that of the endogenous gene. Driven by the homologous rat CRIP promoter, expression increased threefold to sevenfold in intestine, thymus, spleen, and lung over endogenous levels. The transgenic mice had only about 50% of the white blood cell count found in nontransgenic animals. Differential leukocyte counts showed transgenic animals had proportionately fewer lymphocytes and more monocytes, eosinophils, neutrophils. Flow cytometry data suggested that mice overexpressing CRIP have more CD4+/CD8+ thymic lymphocytes. These data suggest that CRIP plays a significant role in differentiation or maturation of cells with rapid turnover such as those found in the intestine and immune system.
Davis
B A
BA
Food Science and Human Nutrition Department, Center for Nutritional Sciences, University of Florida, Gainesville 32611, USA.
Blanchard
R K
RK
Lanningham-Foster
L
L
Cousins
R J
RJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers; D005796:Genes; D060588:LIM Domain Proteins; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D016335:Zinc Fingers
D002352:Carrier Proteins; C489507:Crip1 protein, mouse; C071434:Crip1 protein, rat; D017931:DNA Primers; D060588:LIM Domain Proteins; D012333:RNA, Messenger