Identification of ISG12b as a putative interferon-inducible adipocytokine which is highly expressed in white adipose tissue.
OBJECTIVE
A number of adipocytokines have been suggested to be involved in the disruption of glucose metabolism, and also in the development of various diabetic complications. We attempted to identify and analyze additional adipocytokines, to better understanding the roles of adipocytes and adipocytokines.


METHODS
An oligo-capping signal sequence trap, developed in our laboratory for screening the cDNAs of secretory proteins, was used to sreen cDNAs expressed in mouse white adipose tissue. Profiles of the genes identified in mice and cultured cells were further investigated by northern blotting and luciferase assay.


RESULTS
A cDNA fragment of interferon-stimulated gene 12b (ISG12b) was obtained in the search. A northern blot analysis revealed ISG12b to be highly expressed in white adipose tissue. Interferon alpha (IFNalpha) was shown to induce ISG12b expression in the adipose tissue of BL6 mice in vivo, and also in a 3T3-L1 preadipocyte cell line in vitro. The level of ISG12b was higher in mature adipocytes than in preadipocytes. A promoter analysis demonstrated that the 369bp upstream from the transcription initiation site of ISG12b mRNA contain strong promoter activity, and the interferon-stimulated response elements (ISREs) were not present within the 5593bp upstream region.


CONCLUSIONS
ISG12b is an additional candidate for a adipocytokine induced to express in adipose tissue by interferon.
Ohgaki
Satoko
S
Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Ibaraki, Japan.
Iida
Kaoruko
K
Yokoo
Tomotaka
T
Watanabe
Kazutoshi
K
Kihara
Rumi
R
Suzuki
Hiroaki
H
Shimano
Hitoshi
H
Toyoshima
Hideo
H
Yamada
Nobuhiro
N
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000502:physiology*; D052436:Adipose Tissue, White / Q000502:physiology*; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D016207:Cytokines / Q000235:genetics* / Q000502:physiology; D018076:DNA, Complementary; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology; D005820:Genetic Testing; D007372:Interferons / Q000502:physiology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D008820:Mice, Obese; D011401:Promoter Regions, Genetic / Q000502:physiology; D013047:Specific Pathogen-Free Organisms
D016207:Cytokines; D018076:DNA, Complementary; D008565:Membrane Proteins; D007372:Interferons