A cDNA clone containing the entire coding sequence of a mouse H-2Kd histocompatibility antigen

We have isolated a cDNA clone carrying a 1560 bp long insert which contains the entire coding and 3' untranslated regions of an H-2K(d) mouse histocompatibility antigen. Its sequence and overal features are described. They point to the existence of unique properties of DNA sequences associated with the H-2K(d) antigen.     

Secondary and Apparent Primary Antibody Responses After Group A Streptococcal Vaccination of 21 Children

A partially purified M protein, extracted from a mouse-virulent strain of type 3, group A streptococcus, was administered subcutaneously in gradually increasing amounts at weekly intervals to 21 children in a Family Program. Seven children with type 3 bactericidal antibody in prevaccination sera showed a secondary response. Of 14 children with no detectable type 3 bactericidal antibody prior to vaccination, 13 developed definite type 3 antibody during or soon after vaccination. This response appeared to be of the primary variety in at least some of the 13 children because (i) the total incidence of antibody response (20 of 21) was greater than can be accounted for by the documented incidence of clinical and subclinical type 3 infections among children of our Family Program during a period of 14 years, (ii) the response in the 13 children with no detectable antibody prior to vaccination was more delayed than in those showing a definite secondary response, and (iii) on the average, the amount of vaccine needed for a response in these 13 children was 15 to 28 times greater than that required for the secondary response. Local skin reactions were variable among the vaccinated children. Systemic reactions were infrequent and not severe. The giving of multiple injections of partially purified M protein did not seem to cause cutaneous hypersensitivity.     

Evolution of collagen IV genes from a 54-base pair exon: A role for introns in gene evolution

The exon structure of the collagen IV gene provides a striking example for collagen evolution and the role of introns in gene evolution. Collagen IV, a major component of basement membranes, differs from the fibrillar collagens in that it contains numerous interruptions in the triple helical Gly-X-Y repeat domain. We have characterized all 47 exons in the mouse alpha 2(IV) collagen gene and find two 36-, two 45-, and one 54-bp exons as well as one 99- and three 108-bp exons encoding the Gly-X-Y repeat sequence. All these exons sizes are also found in the fibrillar collagen genes. Strikingly, of the 24 interruption sequences present in the alpha 2-chain of mouse collagen IV, 11 are encoded at the exon/intron borders of the gene, part of one interruption sequence is encoded by an exon of its own, and the remaining interruptions are encoded within the body of exons. In such "fusion exons" the Gly-X-Y encoding domain is also derived from 36-, 45-, or 54-bp sequence elements. These data support the idea that collagen IV genes evolved from a primordial 54-bp coding unit. We furthermore interpret these data to suggest that the interruption sequences in collagen IV may have evolved from introns, presumably by inactivation of splice site signals, following which intronic sequences could have been recruited into exons. We speculated that this mechanism could provide a role for introns in gene evolution in general.     

Modified, large-scale purification of the cytochrome o complex (bo-type oxidase) of Escherichia coli yields a two heme/one copper terminal oxidase with high specific activity.

The cytochrome o complex is a bo-type ubiquinol oxidase in the aerobic respiratory chain of Escherichia coli. This complex has a close structural and functional relationship with the eukaryotic and prokaryotic aa3-type cytochrome c oxidases. The specific activity, subunit composition, and metal content of the purified cytochrome o complex are not consistent for different preparative protocols reported in the literature. This paper presents a relatively simple preparation of the enzyme starting with a strain of Escherichia coli which overproduces the oxidase. The pure enzyme contains four subunits by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Partial amino acid sequence data confirm the identities of subunit I, II, and III from the SDS-PAGE analysis as the cyoB, cyoA, and cyoC gene products, respectively. A slight modification of the purification protocol yields an oxidase preparation that contains a possible fifth subunit which may be the cyoE gene product. The pure four-subunit enzyme contains 2 equivs of iron but only 1 equiv of copper. There is no electron paramagnetic resonance detectable copper in the purified enzyme. Hence, the equivalent of CuA of the aa3-type cytochrome c oxidases is absent in this quinol oxidase. There is also no zinc in the purified quinol oxidase. Finally, monoclonal antibodies are reported that interact with subunit II. One of these monoclonals inhibits the quinol oxidase activity of the detergent-solubilized, purified oxidase. Hence, although subunit II does not contain CuA and does not interact with cytochrome c, it still must have an important function in the bo-type ubiquinol oxidase.