Correlation of two-hybrid affinity data with in vitro measurements.

Since their introduction, the interaction trap and other two-hybrid systems have been used to study protein-protein interactions. Despite their general use, little is known about the extent to which the degree of protein interaction determined by two-hybrid approaches parallels the degree of interaction determined by biochemical techniques. In this study, we used a set of lexAop-LEU2 and lexAop-lacZ reporters to calibrate the interaction trap.

p16 proteins from melanoma-prone families are deficient in binding to Cdk4.

The tumor suppressor candidate p16INK4 is a cyclin-dependent kinase inhibitor that inhibits cell proliferation. The p16 coding gene is often mutated in glioblastomas, pancreatic adenocarcinomas and melanoma-prone pedigrees, but, until recently, the significance of these allelic variants has remained unclear. Here, we used interaction mating and coprecipitation to measure interaction of seven p16 allelic variants detected in melanoma-prone pedigrees with Cyclin-dependent kinases (Cdks).

Murine chromosomal location of five bHLH-Zip transcription factor genes.

The genes for the bHLH-Zip transcription factors Tfap4, Mxi1, Tcfeb, Usf1, and Usf2 have been mapped in mouse by interspecific backcross analysis. Mxi1, Usf1, and Usf2 have been mapped previously by in situ hybridization, but their positions on the meiotic linkage map had not been determined. The other two genes have not previously been mapped in mouse.

APC binds to the novel protein EB1.

Mutations of the APC gene play a critical role in both sporadic and familial forms of colorectal cancer. The vast majority of these mutations result in the loss of the carboxyl terminus of the protein. To further elucidate the function of APC, we searched for cellular proteins that associate with its carboxyl terminus.

Human RNA polymerase II subunit hsRPB7 functions in yeast and influences stress survival and cell morphology.

Using a screen to identify human genes that promote pseudohyphal conversion in Saccharomyces cerevisiae, we obtained a cDNA encoding hsRPB7, a human homologue of the seventh largest subunit of yeast RNA polymerase II (RPB7). Overexpression of yeast RPB7 in a comparable strain background caused more pronounced cell elongation than overexpression of hsRPB7. hsRPB7 sequence and function are strongly conserved with its yeast counterpart because its expression can rescue deletion of the essential RPB7 gene at moderate temperatures.

Bendectin: review of the medical literature of a comprehensively studied human nonteratogen and the most prevalent tortogen-litigen.

Objective: to review the extensive literature pertaining to the reproductive and teratogenic effects of Bendectin and the opinions of the scientific experts for the defense and plaintiff. These data were evaluated with regard to the reproductive risks of Bendectin providing a scientific framework for evaluating the views of the experts in the Bendectin litigation.

Design: the Bendectin literature was primarily obtained from articles cited in Research Alert of the Institute for Science Information.

Postnatal neurophysiologic effects of prenatal X-irradiation.

Histological and neurophysiological effects of in utero irradiation were examined following exposure of pregnant Wistar rat to 2.0 Gy X-irradiation or sham-irradiated on the 17th day of gestation. The 234 newborns were monitored for the age of appearance of four selected physiologic markers and the age of acquisition of five selected reflexes.

Two classes of proteins dependent on either the presence or absence of thyroid hormone for interaction with the thyroid hormone receptor.

The thyroid hormone (T3) receptors (TRs) are hormone-dependent transcription factors that regulate expression of a variety of specific target genes. To help elucidate the mechanisms that underlie this transcriptional regulation and other potential TR activities, we used the yeast interaction trap to isolate clones encoding proteins that specifically interact with the ligand binding domain of the rat TR beta. Several such proteins, called Trips (TR-interacting proteins), were isolated from independent selections carried out either in the presence or absence of T3.

Interaction mating reveals binary and ternary connections between Drosophila cell cycle regulators.

We characterized interactions between Drosophila melanogaster cell cycle regulatory proteins by a yeast interaction-mating technique. The results were displayed as two-dimensional matrices that revealed individual binary interactions between proteins. Each protein (Cdi, cyclin-dependent kinase interactor) interacted with a distinct spectrum of cyclin-dependent kinases (Cdk) from Drosophila and other organisms.

Groucho is required for Drosophila neurogenesis, segmentation, and sex determination and interacts directly with hairy-related bHLH proteins.

We have used the interaction trap, a yeast two-hybrid system, to identify proteins interacting with hairy, a basic-helix-loop-helix (bHLH) protein that represses transcription during Drosophila embryonic segmentation. We find that the groucho (gro) protein binds specifically to hairy and also to hairy-related bHLH proteins encoded by deadpan and the Enhancer of split complex. The C-terminal WRPW motif present in all these bHLH proteins is essential for this interaction.

The effects of prenatal ultrasound exposure on postnatal growth and acquisition of reflexes.

The examination of pregnant women using diagnostic ultrasound has increased greatly over past decades in the United States. As sonography techniques have been altered and refined, there has been renewed interest concerning possible effects on the developing fetus, since exposures in mid-gestation occur during the sensitive period of brain development. The present study is concerned with possible neonatal functional deficits due to exposure of the fetus to ultrasound.

Applications of interaction traps/two-hybrid systems to biotechnology research.

Two-hybrid methods provide a simple and sensitive means to detect the interaction between two proteins in living cells. Their use has resulted in the isolation of new proteins and has facilitated characterization of particular protein-protein interactions. These techniques have already resulted in the identification of important targets for pharmaceutical intervention, and it is likely that their extension in coming years will facilitate the development of new drugs.

The contribution of environmental teratogens to embryonic and fetal loss.

Environmental causes of human malformations account for approximately 10% of malformations, and less than 1% of all human malformations are related to prescription drug exposure, chemicals, or radiation. Malformations caused by drugs and other therapeutic agents are important, however, because these exposures are preventable. As we better understand the mechanisms of teratogenesis from all etiologies, we may learn how best to predict and test for teratogenicity and apply this knowledge to the prevention of human birth defects.

Rch1, a protein that specifically interacts with the RAG-1 recombination-activating protein.

RAG1 and RAG2 are lymphoid-specific genes that together induce V(D)J recombinase activity in a variety of nonlymphoid cell types. While no other lymphoid-specific factors are required to induce recombination, other factors with more widespread expression patterns have been implicated in the reaction. However, none of these factors have been cloned, and their relationship to the RAG proteins is unclear.

Effects of dose and dose protraction on embryotoxicity of 14.1 MeV neutron irradiation in rats.

The embryotoxic effects of neutron radiation on rodent embryos are documented, but there is disagreement about the dose-response relationship and the impact of protracting the dose. Pregnant rats were exposed to total absorbed doses of 0.15 to 1.

Specific DNA recognition and intersite spacing are critical for action of the bicoid morphogen.

We examined DNA site recognition by Bicoid and its importance for pattern formation in developing Drosophila embryos. Using altered DNA specificity Bicoid mutants and appropriate reporter genes, we show that Bicoid distinguishes among related DNA-binding sites in vivo by a specific contact between amino acid 9 of its recognition alpha-helix (lysine 50 of the homeodomain) and bp 7 of the site. This result is consistent with our earlier results using Saccharomyces cerevisiae but differs from that predicted by crystallographic analysis of another homeodomain-DNA interaction.

Amino acid requirements in the early post-implantation rat conceptus.

Amino acid analysis has been performed on hydrolysates of embryos/fetuses, visceral yolk sacs and ectoplacental cones/placentae from early post-implantation rat conceptuses. The increments in each amino acid between 10.5 and 11.

Mapping of two genes encoding members of a distinct subfamily of MAX interacting proteins: MAD to human chromosome 2 and mouse chromosome 6, and MXI1 to human chromosome 10 and mouse chromosome 19.

Both the MAD and the MXI1 genes encode basic-helix-loop-helix-leucine zipper (bHLH-Zip) transcription factors which bind Max in vitro, forming a sequence-specific DNA-binding complex similar to the Myc-Max heterodimer. Mad and Myc compete for binding to Max. In addition, Mad has been shown to act as a transcriptional repressor while Myc appears to function as an activator.

Comparative effects of neutron irradiation and X irradiation on the embryonic development of the rat.

Our aim was to compare the dose-response relationship for the embryotoxic effects of 0.43 MeV neutrons with those of 240 kVp X rays after in utero exposures during early organogenesis in the rat. At 9.

Pinocytosis in the rat visceral yolk sac: potential role in amino acid nutrition during the fetal period.

At 9.5 to 10.5 days post-conception (p.