Cloning of cDNA and the gene encoding human hepatocyte nuclear factor (HNF)-3 beta and mutation screening in Japanese subjects with maturity-onset diabetes of the young.
OBJECTIVE
Molecular defects of the genes for transcription factors, hepatocyte nuclear factor (HNF)-4 alpha, HNF-1 alpha, HNF-1 beta and insulin promoter factor-1 cause maturity-onset diabetes of the young (MODY1, 3, 5, and 4, respectively). This suggests the HNF-related transcription cascade is important in insulin secretion which is induced by glucose. These genes and the gene encoding glycolytic enzyme glucokinase (MODY2) are, however, responsible for only 15-20% of cases of MODY in the Japanese. Searching for a novel form of MODY in this population, we cloned a new candidate gene encoding human HNF-3 beta, a winged helix transcription factor, which also belongs to the same HNF-transcription cascade.


METHODS
The cDNA clone for human HNF-3 beta was isolated from a liver cDNA library. The gene was also cloned from a genomic library and its organization and chromosomal localization were determined. We screened 68 Japanese subjects with MODY/early-onset diabetes for mutations in this gene.


RESULTS
Human HNF-3 beta is composed of 457 amino acids. The human gene, which was mapped to the segment 30 cR from SHGC-37039 on chromosome 20p by radiation hybrid mapping, spans approximately 4.5 kb and consists of three exons. Direct sequencing of the exons and flanking regions identified one missense mutation A328 V and seven polymorphisms, although the functional significance of the mutation in the pathogenesis of diabetes is not known.


CONCLUSIONS
The characterization of the structure of the HNF-3 beta gene and its mapping in the framework of markers will be helpful in genetic studies of the various forms of diabetes mellitus.
Yamada
S
S
Department of Cell Biology, Gunma University, Japan.
Zhu
Q
Q
Aihara
Y
Y
Onda
H
H
Zhang
Z
Z
Yu
L
L
Jin
L
L
Si
Y J
YJ
Nishigori
H
H
Tomura
H
H
Inoue
I
I
Morikawa
A
A
Yamagata
K
K
Hanafusa
T
T
Matsuzawa
Y
Y
Takeda
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D002890:Chromosomes, Human, Pair 20; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005091:Exons; D015723:Gene Library; D015698:Genomic Library; D051542:Hepatocyte Nuclear Factor 3-beta; D006801:Humans; D007438:Introns; D007564:Japan; D008099:Liver / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics*; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics; D014981:Xenopus; D015027:Zebrafish
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C496502:FOXA2 protein, human; C496503:Foxa2 protein, mouse; C496504:Foxa2 protein, rat; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D051542:Hepatocyte Nuclear Factor 3-beta