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The DNA strands of lambdoid phages with deletions or substitutions of the guanine plus cytosine-rich region in the left arm are not resolvable by complexing with poly UG followed by centrifugation in CsCl. This work describes a completely general procedure for the strand resolution of these phages by hybridization with fragments of separated strands of the parent phage. In particular, resolution of the DNA strands of the specialized transducing phage lambda-h80C1-857dargF is described, and evidence is presented which indicates that argF is transcribed from the r strand.

Ribonucleic acid-deoxyribonucleic acid (RNA-DNA) hybridization was employed for the determination of the level of messenger RNA (mRNA) transcribed from seven of the nine genes of the arginine regulon of Escherichia coli K-12. The quantity of RNA complexing with each of the separated DNA strands of the argA, argF, argE, and argCBH operons carried on specialized transducing phages was measured. The derepressed:repressed ratio of mRNA formed in vivo was found to vary between about 3 and 4 when measured by hybridization to DNA isolated from specialized transducing phages carrying the argA, argE, argCBH, argF, and argI operons.

The directed transposition of argF to the tonB locus of the Escherichia coli chromosome and the subsequent isolation of the specialized transducing phage phi80dargF is described. The structure of this phage has been has been determined. A hybrid lambdah80cI857dargF phage has been constructed. Deoxyribonucleic acid isolated from these and their parent bacteriophages has been specifically cleaved by the endonucleases EcoRI and SmaR; the unique deoxyribonucleic acid fragments thus obtained have been resolved and analyzed by electrophoresis in agarose gel.

The localization of Thy-1, a surface membrane lipoglycoprotein, was investigated using a monoclonal antibody specific for human Thy-1 (HB-2S-1). The localization of Thy-1 during development was established in a series of five fetal, three childhood, and two adult normal kidneys. In this series, Thy-1 immunolocalization progressed from mesangial and endothelial cell staining in the 16- to 17-week fetuses to similar staining along with staining of the parietal epithelium of the capsule and proximal tubule staining in the 20- to 24-week fetuses. Glomerular mesangial cell and endothelial cell staining was absent by 9 months postnatally when the adult pattern of staining was apparent. The localization of Thy-1 during development was also compared with a series of pediatric renal tumors including 14 Wilms' tumors, 3 congenital mesoblastic nephromas, 1 clear cell sarcoma, and 1 pediatric renal cell carcinoma. Thy-1 staining was demonstrated in epithelial tubules of Wilms' tumors and in the spindle-shaped cells of congenital mesoblastic nephroma correlating with Thy-1 immunoreactivity in the kidney proximal tubule and fetal medullary stroma, respectively. Thy-1 staining was absent in the anaplastic epithelial Wilms' tumor, the renal cell carcinoma, and the clear cell sarcoma. This staining pattern fails to provide evidence that these tumors may arise from the medullary mesenchyme or the differentiated

Current evidence indicates that the defect in cystic fibrosis (CF) involves chloride transport in various epithelial cells. The sweat gland, one site of altered chloride transport in CF, was examined immunocytochemically for localization of a chloride-channel membrane protein, designated band 3 protein. Immunoreactivity was observed in sweat duct cell membranes of both normal and CF samples, whereas secretory coil regions were entirely unreactive. No difference was observed in the pattern or intensity of immunoreactivity between the two groups at the light microscopic (LM) level of resolution.

Tumor suppressor genes have been found to have loss of function in a number of malignancies. This loss of function is believed to contribute to malignant transformation or metastatic spread. In the present study, expression of the retinoblastoma (RB) tumor suppressor gene was examined in cell lines and tumor tissue obtained from primary renal and metastatic sites in patients with metastatic renal cell carcinoma. Three of fifteen (20 percent) of informative renal carcinoma cell lines had loss of heterozygosity (LOH) in the RB gene (intron 20) detected by polymerase chain reaction analysis. Using restriction fragment length polymorphism (RFLP) analysis, 7 of 22 (32 percent) informative cell lines had LOH centromeric to the RB gene at the D13S1 locus. No LOH (0 of 7) was seen telomeric to the RB gene at the D13S2 locus. None of the 28 cell lines examined had decreased RB mRNA expression compared with short-term cultures of proximal renal tubular cells. Western blotting demonstrated phosphorylated and unphosphorylated forms of RB protein of expected molecular weight in all 41 cell lines (33 primary and 8 metastatic) examined. Twenty-nine primary cell lines and 6 metastatic cell lines all demonstrated normal immunohistochemical staining. Loss of RB immunohistochemical staining in paraffin-embedded tissue was detected in none of the primary tumors (0 of 30) or metastatic tumors (0 of 12). The absence of abnormalities of RB expression detected in these renal cell carcinomas suggests that abnormalities of the RB gene are not central to malignant transformation or progression in this tumor type; however, another tumor suppressor gene centromeric to the RB locus may be important in renal cell carcinogenesis.

Deoxyribonucleic acid isolated from argA and argECBH transducing phages was utilized to study the in vitro synthesis of argA, argE, and argCBH messenger ribonucleic acid. The specific regulation of these operons by the arginine holorepressor was demonstrated, providing evidence that the majority, if not all, of the control of these operons is exercised at the transcriptional level. Data are presented which indicate that the arginine holorepressor functions by binding to the operator region and concomitantly prevents the binding of ribonucleic acid polymerase to the corresponding promoter region.