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P Rotwein

Publications and source records attributed to P Rotwein.

95 records · Page 6Linked to original sources
PubMed1983

Analysis of insulin gene expression in human pancreas.

The purpose of these studies was to determine whether insulin gene expression at the level of proinsulin mRNA could be studied in human pancreas. RNA was isolated from autopsy specimens and analyzed by RNA-blot hybridization with various 32P-human insulin gene probes spanning either the entire gene or the second intervening sequence. A major band 0.62 kilobases (kb) in length accounted for over 95% of the mRNA, consistent in size with presumed mature proinsulin mRNA. In addition, minor bands of 1.5 and 1.3 kb were seen, consistent with an initial gene transcript containing both intervening sequences and with a processed intermediate. The 1.5- and 1.3-kb RNA were confirmed to be proinsulin mRNA precursors by hybridization specifically with the IVS II probe. Total RNA and polyadenylated RNA from five normal pancreata and two insulinomas revealed the same pattern. This method provides a means of determining whether altered insulin gene expression is one cause of diabetes.

Diabetes Mellitus↗
PubMed1981

Polymorphism in the 5'-flanking region of the human insulin gene and its possible relation to type 2 diabetes.

The arrangement of the human insulin gene in DNA from 87 individuals was analyzed by the Southern blot hybridization technique with a cloned genomic human insulin probe. Insertions of 1.5 to 3.4 kilobase pairs in the 5'-flanking region of the gene were found in DNA from 38 individuals. These insertions occurred within 1.3 kilobase pairs of the transcription initiation site. In contrast, no insertions were observed in the region 3' to the coding sequence. The prevalence of these insertions in type 2 diabetes was significantly greater than in the other groups (P less than .001). The limitation of this striking length polymorphism to a potential promoter region suggests that these insertions may play a role in insulin gene expression.

Base Sequence↗
PubMed1981

Insulin biosynthesis and diabetes mellitus.

This review reports the use of recombinant DNA techniques in the study of the structure and regulation of expression of insulin genes in man and experimental animals. Insulin biosynthesis by pancreatic islet cells is predominantly regulated by change in plasma glucose concentration. Using a cell-free protein synthesizing system as an assay of functional proinsulin messenger RNA (mRNA), and hybridization analysis with a cloned DNA complementary to proinsulin mRNA, it has been determined that through changes in proinsulin mRNA levels. Insulin genes of the rat, chicken and human have been isolated and sequenced. The 5' ends of the genes have similar sequences suggesting areas important for regulation of transcription. There are two non-allelic insulin genes in the rat, but only one in chickens and humans. Intervening sequences, areas of DNA transcribed into precursor mRNA but which do not appear in mature mRNA, have been described within insulin genes. The insulin gene resides on chromosome 11 of humans as determined by DNA hybridization analysis of mouse human hybrid cells. The structure of the insulin gene in genomic DNA of humans has been analyzed in diabetics and non-diabetics. Insertions of DNA between 1500 and 3400 base pairs have been detected near the transcription initiation site in 65% of type II diabetics, and 25-30% of non-diabetics (this difference is significant at the p less than 0.001 level). Limitation of these insertions to this potential promotor region of the insulin gene suggests that they may alter gene expression in type II diabetes. These insertions of DNA may prove to be useful genetic markers for diabetes.

Animals↗
PubMedDate not supplied

Insulin gene structure and function: a review of studies using recombinant DNA methodology.

This review focuses on recent advances in molecular biology as they pertain to the insulin gene and diabetes mellitus. The structure of the human insulin gene is examined, and factors related to its normal functioning in the beta cells of the pancreas are explored. DNA polymorphisms near the insulin locus and their relationship with certain types of diabetes are considered, as are recently characterized human insulin gene mutations. Events in animal models for diabetes that reflect altered insulin gene expression are discussed and the potential application of gene therapy in human diabetes is examined. Recombinant DNA methodology holds great promise as a tool for providing better understanding of the causes of diabetes and potential curative treatment.

Animals↗