Nucleotide sequence of the yeast regulatory gene STE7 predicts a protein homologous to protein kinases.

The nucleotide sequence of the STE7 gene from Saccharomyces cerevisiae has been determined. It is one of several regulatory genes implicated in the control of cell-type-specific gene expression in yeast. The predicted amino acid sequence shows homology to several members of the protein kinase family. These results suggest protein phosphorylation may play a key role in regulation leading to cell-type specialization in yeast.

Identification of regulatory regions within the Ty1 transposable element that regulate iso-2-cytochrome c production in the CYC7-H2 yeast mutant.

The CYC7-H2 mutation in the yeast Saccharomyces cerevisiae was caused by insertion of a Ty1 transposable element in front of the iso-2-cytochrome c structural gene, CYC7. The Ty1 insertion places iso-2-cytochrome c production under control of regulatory signals that are normally required for mating functions in yeast cells. We have investigated the regions of the Ty1 insertion that are responsible for the aberrant production of iso-2-cytochrome c in the CYC7-H2 mutant. Five alterations of the CYC7-H2 gene were obtained by specific restriction endonuclease cleavage of the cloned DNA and ligation of appropriate fragments. The CYC7+, CYC7-H2, and modified CYC7-H2 genes were each inserted into the yeast vector YIp5 and used to transform a cytochrome c-deficient yeast strain. Expression and regulation of each allele integrated at the CYC7 locus have been compared in vivo by determination of the amount of iso-2-cytochrome c produced. These results show that distal regions of the Ty1 element are not essential for the CYC7-H2 overproducing phenotype. In contrast, alterations in the vicinity of the proximal Ty1 junction abolish the CYC7-H2 expression and give rise to different phenotypes.

Method for measurement of circumduction of the thumb to evaluate results of opponensplasty.

A simple method for measuring circumduction of the thumb, by using a ratio of the range of motion to the length of the first metacarpal, is described. This method can be of value in assessing many aspects of thumb function, especially the improvement in function after opponensplasty. The improved ability to position the thumb in a useful location, both for pinch and grasp, appears to correlate well with the patient's use of the hand for previously impossible tasks.

Prevention of extensor lag after indicis proprius tendon transfer.

An experiment on fresh cadaver hands showed that a longitudinal incision of the hood did not affect index extension when traction was made on the common extensor tendon, but that excision of a portion of the hood containing the indicis proprius caused an extensor lag. The lag was eliminated by repair of the hood, providing that the closure was not too tight to prevent normal excursion of the hood. These findings were correlated with findings in patients who had undergone indicis proprius tendon transfer. Extensor lag after indicis proprius transfer is not caused by removal of the force of the tendon per se, but by factors which cause either disruption of normal hood function or tethering of its normal excursion.

Burn syndactyly.

When the entire digital web space has been destroyed by burn scarring and there is a contracture of the volar aspect of the web as well as the dorsum, Z-plasties and skin grafts alone seldom produce a satisfactory web space. During the past 3 years, for the release of 46 contracted web spaces in 20 burned patients, we have turned a rectangular flap from the dorsal surface of the web through into an inverted-T incision in the palm. The adjacent sides of the defects have been skin grafted. In all these patients, we obtained satisfactory release of the contracture and restoration of the web space.