Structural and functional variability among DQ β alleles of DR2 subtypes

Homozygous lymphoblastoid cell lines representing various Dw subtypes of DR2 were examined for polymorphism at the DQ locus by molecular and cellular techniques. The subtypes studied included Dw2, Dw12, and a group heterogenous by cellular typing that we shall refer to as non-Dw2/non-Dw12. Restriction fragment length polymorphism analysis of cell lines representing these subtypes revealed DQ -specific patterns consistent with cellular typing. Two-dimensional gel electrophoresis of DQ molecules from representative cell lines revealed a structural polymorphism of DQ among the three subtypes. The DQ chain migrated to a position that was unique to each subtype and was consistent among various representative cell lines of each subtype. Nucleotide sequence analysis of cDNA clones of DQ from Dw2, Dw12, and non-Dw2/non-Dw12 lines confirmed that the variability resided at the genetic level. Variability was found in the form of numerous scattered nucleotide substitutions throughout the first domain of these alleles. The DQ gene of the non-Dw2/non-Dw12 cell line AZH was further found to be almost identical with the DQ gene of a DR1 line (Bell et al. 1985b), implicating a common evolutionary origin of these alleles. The only difference between these two sequences was due to an apparent gene conversion event at amino acid 57. T-cell cloning experiments resulted in the derivation of Epstein-Barr virus-specific, DQw1-restricted clones that proliferated against only those cell lines that exhibited the DQ gene common to AZH and the DR1 cell line. Thus, the polymorphism among DQ alleles within DR2 results in subtype-specific restriction.     

Immunochemical detection, physicochemical characterization and levels of pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG) in seminal plasma of men

Pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG), the major secretory protein of the human uterine endometrium during the luteal phase of the menstrual cycle and early first trimester of pregnancy, has been detected by immunochemical techniques in seminal plasma. Biochemical analysis and immunoblotting has verified that immunoreactive alpha 2-PEG in seminal plasma exhibits properties identical to those of endometrial alpha 2-PEG, i.e. Concanavalin A-binding dimeric glycoprotein of native Mr 56,000, subunit Mr 28,000, average pI 4.7 and of alpha 2-mobility. Concentration of alpha 2-PEG in seminal plasma was 22.13 +/- 2.82 micrograms/ml (mean +/- s.e.m., n = 110) which compared to 12.02 +/- 1.65 micrograms/ml (mean +/- s.e.m., n = 48) found in amniotic fluid at 11-20 weeks of pregnancy, to 4.29 +/- 1.66 micrograms/ml (mean +/- s.e.m., n = 15) in uterine luminal fluid in women during the luteal phase and to 0.245 +/- 0.025 micrograms/ml (mean +/- s.e.m., n = 10) in sera at 10 weeks of pregnancy. This distribution is very different from that observed for pregnancy-associated placentally-derived serum proteins detected in seminal plasma. The source of alpha 2-PEG in seminal plasma is unknown but is unlikely to be the testis because of the normal levels observed in vasectomized men. In the endometrium alpha 2-PEG synthesis and secretion appears to be related to progesterone-dependent differentiation of the glandular epithelium. Therefore these observations suggest that a different mechanism of regulation of the gene for alpha 2-PEG operates in the male reproductive tract.     

Two Agrobacterium tumefaciens genes for cytokinin biosynthesis: Ti plasmid-coded isopentenyltransferases adapted for function in prokaryotic or eukaryotic cells

Summary Tzs and ipt are two Ti plasmid genes coding for proteins with isopentenyltransferase (IPT) activity in vitro. We cloned both genes for protein expression in Escherichia coli and in Agrobacterium tumefaciens, and we investigated differences between the two genes by analysing the properties of the proteins in vitro and in vivo. In vitro, extracts with tzs or ipt-coded proteins had high IPT activity, and the enzymes were identical in most properties. The most important difference was detected in vivo: the tzs-encoded protein was very active in cytokinin production, while the ipt protein required overexpression in order to obtain measurable activity in bacteria. In both cases, rans-zeatin was the major product of the gene activity. Formation of this cytokinin requires a hydroxylase function in addition to the IPT reaction. No such activity could be ascribed to tzs or ipt-encoded proteins in vitro or in vivo, but cytokinin hydroxylase activity was detected in cells and extracts of E. coli, regardless of the presence or absence of the cytokinin genes. Based on these results it is proposed that both genes code for a single enzyme activity (isopentenyltransferase), that the genes and proteins are adapted for function either in bacteria (tzs) or in transformed plant cells (ipt), and that in both prokaryotic and eukaryotic cells hydroxylation to trans-zeatin is a function contributed by host enzymes.Abbreviations DMAPP dimethylallylpyrophosphate - iP isopentenyladenine - iPA isopentenyladenosine - iPMP isopentenyladenosine 5-monophosphate - IPT isopentenyltransferase - trans-Z trans-zeatin     

Molecular mapping of class II polymorphisms in the human major histocompatibility complex. I. DR beta

We have studied 27 cell lines homozygous by consanguinity for the major histocompatibility complex to establish the restriction fragment length polymorphism (RFLP) patterns seen with six different restriction enzymes (Bam HI, Bg1 II, Eco RI, Hinc II, Hind III, Pvu II) and DR beta chain probes. The probes used were a full-length cDNA DR beta probe and a probe specific for the 3' untranslated region. The RFLP obtained represent the first standard patterns for the individual haplotypes DR1 through 7 and DR9 as defined by genetically homozygous lines. The patterns obtained reflect the DR specificities closely, as well as the DRw52 and DRw53 specificities. These latter specificities are associated with the most prominent patterns of RFLP. Bands are present which are unique for the haplotypes DR1, DR2, DR4, DR7, DRw52, and DRw53, and could be used for typing these haplotypes in heterozygotes. Subtypes can be identified for all of the haplotypes except DR1. These subtypes indicate that there is an extensive amount of polymorphism in the DR subregion that has not been identified serologically.     

Cytologic features of islet-cell tumors

Although a number of reports have demonstrated the accuracy of fine needle aspiration (FNA) in the diagnosis of nonendocrine pancreatic carcinomas, the cytomorphology of islet-cell tumors (pancreatic endocrine tumors) is not well defined. This paper describes the cytologic features of three histologically confirmed cases of islet-cell tumors. The three tumors occurred in one man and two women, who were 63, 64 and 70 years of age, respectively. Each patient underwent FNA of pancreatic mass with computed body tomography guidance. The aspirates contained large numbers of tumor cells in two cases and a smaller number in one case. The cells, distributed singly and in small groups, were small and round or polygonal, with scant to more often abundant, dense or granular cytoplasm. The nuclei were often located eccentrically and were round to oval, with smooth nuclear borders and finely stippled chromatin. Many nuclei contained a single nucleolus. Multinucleated cells were present and generally contained two or three nuclei. Although the diagnosis of islet-cell tumors in fine needle aspirates is difficult, the cytomorphologic features of these tumors are sufficiently distinctive to suggest the diagnosis, especially when a relatively monomorphic population composed predominantly of single cells is present.