Structure of the murine lck gene and its rearrangement in a murine lymphoma cell line

The lck gene encodes a lymphocyte-specific protein-tyrosine kinase that is implicated in neoplastic transformation. We have determined the germ line organization of the murine lck gene and have isolated and characterized a rearranged lck allele in the murine lymphoma cell line LSTRA. The overall exon-intron organization of the normal lck gene is almost identical to that of avian c-src. In LSTRA DNA, an internally rearranged Moloney murine leukemia virus genome is interposed between two distinct promoters that normally generate lck transcripts differing only in 5' untranslated regions. The rearrangement appears to have been selected to permit splicing of transcripts that initiate from the Moloney virus promoter to an acceptor site located within the first exon 3' to the downstream promoter, thus generating an lck mRNA with a novel 5' untranslated region that may be more efficiently translated.

Efficient coupled transcription and mRNA splicing in vitro using plasmids derived from early region 3 of adenovirus 2 and a nondefective adenovirus-simian virus 40 hybrid

Accurate and highly efficient (80%) splicing of a single mRNA precursor to processed products was achieved using HeLa cell extracts to synthesize and process RNA in vitro from recombinant plasmids containing specific DNA segments from adenovirus 2 (Ad2) and the nondefective adenovirus-simian virus 40 (Ad+2ND1) hybrid. One plasmid, pRID, contains a segment of Ad2 DNA spanning chromosome map coordinates 75.9-83.4. The other plasmid, pRW9, contains the analogous viral region from Ad+2ND1. RNA synthesis from pRID in vitro occurs for more than 60 min and is directed by RNA polymerase II. RNA products consistent in size with the expected precursor and the two processed mRNAs are made. RNA blot hybridization analyses showed that these products are complementary to the Ad2 insert in the plasmid and that the appropriate intervening sequence was absent from the smallest processed mRNA. Comparison of the splice patterns of RNA made in vitro to those of RNAs taken from infected cells using the nuclease S1 technique demonstrated the accuracy of intron removal.

Primary amyloidoma of the spine

A rare case of primary solitary amyloidoma involving the dorsal spine is reported. Destruction of the fourth thoracic vertebra and extension of the soft tissue mass around the vertebra were visualized on linear tomography and computed tomography. Diagnosis was made on the basis of histology and histochemical reactions.

Sonography of splenic abscess

Gray-scale sonographic examination was performed in seven cases of splenic and parasplenic abscess. The splenic abscesses appeared as irregular, poorly defined anechoic masses with varying internal echogenicity and acoustical transmission. Increased echogenicity and distal acoustical shadowing due to gas within the abscess were also noted. Gray-scale sonography was instrumental in the diagnosis of splenic abscess in this group of patients whose symptomatology was of uncertain etiology.

Five different enzymatic activities are associated with the multienzyme complex of fatty acid oxidation from Escherichia coli

The purified multienzyme complex of fatty acid oxidation from Escherichia coli was found to possess 3-hydroxyacyl-coenzyme A (CoA) epimerase and cis-delta3-trans-delta2-enoyl-CoA isomerase activities in addition to the previously identified enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and 3-ketoactyl-CoA thiolase activities. Evidence is presented in support of the proposed association of all five enzyme activities with one protein which apparently is composed of two types of subunits and which can exist in several aggregated forms. The five component enzymes of the complex were rapidly inactivated by tris(hydroxymethyl)aminomethane, whereas they remained active in the presence of potassium phosphate.