title: Galectin-12 is required for adipogenic signaling and adipocyte differentiation.
abstract: Galectin-12 is a member of the galectin family consisting of beta-galactoside-binding proteins with conserved carbohydrate recognition domains. This protein is preferentially expressed in peripheral blood leukocytes and adipocytes. We previously showed that galectin-12 is induced by cell cycle block at the G(1) phase and causes G(1) arrest when overexpressed (Yang, R.-Y., Hsu, D. K., Yu, L., Ni, J., and Liu, F.-T. (2001) J. Biol. Chem. 276, 20252-20260). Here, we show that the galectin-12 gene is expressed in mouse preadipocytes and is up-regulated when preadipocytes undergo cell cycle arrest, concomitant with acquisition of the competence to undergo differentiation in response to adipogenic hormone stimulation. Following a brief down-regulation 1 day after adipogenic treatment, its expression was once again markedly elevated when cells underwent terminal differentiation. Down-regulation of endogenous galectin-12 expression by RNA interference greatly reduced the expression of the adipogenic transcription factors CCAAT/enhancer-binding protein-beta and -alpha and peroxisome proliferator-activated receptor-gamma and severely suppressed adipocyte differentiation as a result of defective adipogenic signaling. We conclude that galectin-12 is required for signal transduction that conveys hormone stimulation to the induction of adipogenic factors essential for adipocyte differentiation. The findings suggest that galectin-12 is a major regulator of adipose tissue development.
authors.affiliation: Department of Dermatology, University of California Davis School of Medicine, Sacramento, California 95817, USA. ryyang@ucdavis.edu
authors.forename: Ri-Yao
authors.initials: RY
authors.lastname: Yang
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Hsu
authors.forename: Lan
authors.initials: L
authors.lastname: Yu
authors.forename: Huan-Yuan
authors.initials: HY
authors.lastname: Chen
authors.forename: Fu-Tong
authors.initials: FT
authors.lastname: Liu
mesh_terms: D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology / Q000502:physiology*; D000273:Adipose Tissue / Q000166:cytology / Q000502:physiology*; D000818:Animals; D015415:Biomarkers; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D037161:Galectins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D015415:Biomarkers; D018797:Cell Cycle Proteins; D037161:Galectins; C503649:Lgals12 protein, mouse; D034741:RNA, Small Interfering; D014157:Transcription Factors