Paper Chase is a research database designed to offer abstracts of research articles published in journals that have a highly rated impact factor as determined by ISI Impact Factor and PageRank. Abstracts are organized by date, with the most recently published papers listed first. 

Paper Chase

Mutations at the BLK locus linked to maturity onset diabetes of the young and beta-cell dysfunction.

Proc. Natl. Acad. Sci. U.S.A.. Aug 25, 2009;106(34):14460-5.
Borowiec M, Liew CW, Thompson R, Boonyasrisawat W, Hu J, Mlynarski WM, El Khattabi I, Kim SH, Marselli L, Rich SS, Krolewski AS, Bonner-Weir S, Sharma A, Sale M, Mychaleckyj JC, Kulkarni RN, Doria A.

Research Division, Department of Medicine, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA.

Abstract:

Maturity-onset diabetes of the young (MODY) is a subtype of diabetes defined by an autosomal pattern of inheritance and a young age at onset, often before age 25. MODY is genetically heterogeneous, with 8 distinct MODY genes identified to date and more believed to exist. We resequenced 732 kb of genomic sequence at 8p23 in 6 MODY families unlinked to known MODY genes that showed evidence of linkage at that location. Of the 410 sequence differences that we identified, 5 had a frequency <1% in the general population and segregated with diabetes in 3 of the families, including the 2 showing the strongest support for linkage at this location. The 5 mutations were all placed within 100 kb corresponding to the BLK gene. One resulted in an Ala71Thr substitution; the other 4 were noncoding and determined decreased in vitro promoter activity in reporter gene experiments. We found that BLK--a nonreceptor tyrosine-kinase of the src family of proto-oncogenes--is expressed in beta-cells where it enhances insulin synthesis and secretion in response to glucose by up-regulating transcription factors Pdx1 and Nkx6.1. These actions are greatly attenuated by the Ala71Thr mutation. These findings point to BLK as a previously unrecognized modulator of beta-cell function, the deficit of which may lead to the development of diabetes.