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S D Detera-Wadleigh

Publications and source records attributed to S D Detera-Wadleigh.

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The genomic structure of the human glucocorticoid receptor.

We have determined the structure of the human glucocorticoid receptor (hGR) gene after the isolation and characterization of cosmid clones mapping to discrete regions of the cDNA. The gene contains a total of 10 exons and has a minimum size of 80 kilobases. Exon 1 consists solely of 5'-untranslated sequence, and exon 2 encodes the amino-terminal portion of the receptor. The two putative zinc fingers are separately encoded by two exons, and a total of five exons combine to form the cortisol-binding domain. By restriction mapping and sequence analysis of cosmids located on the 3'-end of the gene, we have established that the two receptor isoforms, hGR alpha and hGR beta, originate from the same gene by alternative splicing. Each hGR isoform is encoded by nine exons, of which the first eight are identical, whereas the ninth exons are heterologous. Multiple GC boxes and no obvious TATA or CAAT elements have been found in the 5'-flanking region. S1 nuclease analysis yielded one major band, and the transcription start site is localized to the *C residue within TAC*CCTC. Alignment of sequences around the splice junctions of hGR with those of other members of the steroid receptor superfamily revealed three different splice positions within the DNA-binding domain. This comparison also permitted the prediction of the positions of the splice sites and the sizes of the putative exons in the human mineralocorticoid receptor.

Amino Acid Sequence↗

H-ras-1 polymorphism in leukemia.

We have examined leukocyte DNAs obtained from 21 patients with various types of leukemia for the Sacl polymorphism of H-ras-1. The patients included ten with B-lineage leukemia, two with T-cell leukemia, and nine with acute myelogenous leukemia. Using a genomic probe for H-ras-1 in Southern hybridizations, we found that 78% of the DNA from leukemias of myeloid origin were heterozygous. In contrast, only three of ten B-cell-derived leukemias showed heterozygosity. This difference in the number of heterozygotes vs. homozygotes in the two patient samples studied is statistically significant (P = 0.04 by Fisher's exact test). These results suggest the possibility that the H-ras-1 allelic pattern that is associated with acute myelogenous leukemia is distinct from that found in B-cell-derived malignancies.

Genes, ras↗

Molecular analysis of microtubule-associated protein-2 kinase cDNA from mouse and rat brain.

We have isolated and characterized brain cDNA clones encoding microtubule-associated protein-2 (MAP-2) kinase for rat (rMNK1) and mouse (mMNK1). The nucleotide sequences diverged by only 5% whereas the amino acid sequences were identical except for one conservative residue change. Conservation of the expressed sequence extended into other mammalian species. These findings constitute the first demonstration of a strict evolutionary conservation of MAP-2 kinase. Genomic restriction patterns revealed a single MAP-2 kinase gene that shares homology with other genomic sequences. The 3' terminal half of the gene appears to be encoded by four exons. rMNK1 and mMNK1 differed from a recently reported MAP-2 kinase cDNA, termed ERK1, because of a nonconservative change in position 82, from Gly in ERK1 to Arg in rMNK1. The rMNK1 gene was found to be expressed mainly as a 1.8-kb transcript that was highest in brain and in lung. In contrast to ERK1, rMNK1 showed two equally prominent mRNA species in liver, at 1.8 kb and 5 kb, which imply differential processing of the primary transcript. Results derived from the immunological screening of an expression library showed that MAP-2 kinase might share epitopes with two prominent protein kinase C substrates, MARCKS (an 80-kD protein kinase C substrate) and GAP-43, suggesting the possibility that MAP-2 kinase could interact with kinase C.

Amino Acid Sequence↗

Exclusion of linkage to 5q11-13 in families with schizophrenia and other psychiatric disorders.

Recently a linkage study on five Icelandic and two English pedigrees has provided evidence for a dominant gene for schizophrenia on 5q11-13 (ref. 1). In that study, families with bipolar illness were not included. Using the same probes, two similar but independent investigations on one Swedish pedigree and on fifteen Scottish families excluded linkage to schizophrenia. To evaluate whether the susceptibility gene on 5q11-13 is a common cause of schizophrenia in other populations, we examined five affected North American pedigrees using probes to the D5S39, D5S76 and dihydrofolate reductase loci. Two families in the present series had cases of bipolar disorder. We found that linkage can be excluded by multipoint analysis. These results, taken together, suggest that the disease gene on 5q11-13 does not account for most cases of familial schizophrenia.

Bipolar Disorder↗

Molecular analysis of human and rat calmodulin complementary DNA clones. Evidence for additional active genes in these species.

A cDNA clone, lambda rCB1, encoding calmodulin was isolated from a rat brain expression library. The sequence was determined and compared to the structures of the previously described rat genes, lambda SC4 and lambda SC8 (Nojima, H., and Sokabe, H. (1986) J. Mol. Biol. 190, 391-400). Faithful sequence conservation is observed in the coding regions of lambda rCB1 and lambda SC4, the bona fide gene. Both cDNAs encode identical amino acid sequence. Very limited sequence homology, however, is noted in the 3'-untranslated segments of these clones. Surprisingly, when the lambda rCB1 nucleotide structure is compared to the processed intronless gene, lambda SC8, extensive sequence homology is found both in the coding and noncoding regions. The inferred protein sequences of lambda SC8 and lambda rCB1, however, are divergent. Using a fragment of lambda rCB1 to screen an expression library derived from a human embryonic cell line, a calmodulin cDNA clone, lambda hCE1, was isolated and characterized. Comparison of the sequence of lambda hCE1 to the cDNA from human liver, hCWP (Wawrzynczak, E. J., and Perham, R. N. (1984) Biochem. Int. 9, 177-185), reveals substantial structural divergence. Strikingly poor homology is seen in the 5'- and 3'-noncoding segments, but the coding regions were 85% homologous. Both lambda hCE1 and hCWP encode proteins of identical primary structure which is equivalent to the protein sequence deduced from lambda rCB1 and lambda SC4. Taken together these results suggest the existence of an additional actively transcribed calmodulin gene, not previously identified, in each of the human and rat genomes. Transcripts of lambda rCB1 and lambda hCE1 were observed in all tissues examined indicating the absence of tissue-specific expression. Calmodulin gene polymorphisms were detected using TaqI, HindIII, and MspI.

Amino Acid Sequence↗

Neuropeptide gene polymorphisms in affective disorder and schizophrenia.

The restriction fragment length polymorphisms (RFLPs) associated with neuropeptide Y (NPY) and somatostatin loci were used to assess the possibility of linkage to a locus for affective disorder (AD). When somatostatin haplotypes were assigned to members of 2 AD pedigrees under either rare dominant or recessive transmission, the LOD scores obtained at 0% recombination were inconsistent with linkage. Similar results were obtained with NPY under rare dominant inheritance. Comparison of the frequency of the genotypes deduced from the polymorphic alleles of gastrin-releasing peptide, NPY, somatostatin and substance P in normals vs patients with either AD or schizophrenia suggests the absence of association. The difference in the frequency of the 3.3 kb adenosine deaminase fragment in normals vs bipolar and schizophrenic patients is of borderline significance.

Adult↗

Close linkage of c-Harvey-ras-1 and the insulin gene to affective disorder is ruled out in three North American pedigrees.

Affective disorder (AD) is one of the major forms of functional psychoses. Although the mode of transmission is uncertain, family, twin and adoption studies strongly suggest a genetic involvement. Because a basic biochemical abnormality is not known, direct analysis of the disease using a probe for the defective gene is not possible. However, a specific locus can be tested for its relevance to the aetiology of AD by genetic linkage, using restriction fragment length polymorphisms (RFLPs). Using probes for the c-Ha-ras-1 oncogene and the insulin gene, Gerhard et al. and Egeland et al. found convincing evidence for close linkage between these markers and a locus for AD in a large Old Order Amish pedigree. In an attempt to confirm this finding, we examined three bipolar pedigrees outside the Amish population. Our results indicate the absence of linkage from 0 to 15% recombination frequency between AD and the insulin gene-HRAS1 region in these pedigrees.

Bipolar Disorder↗

Lack of linkage between the corticotropin-releasing hormone (CRH) gene and bipolar affective disorder.

Corticotropin-releasing hormone (CRH) plays a key role in the regulation of the stress response. Abnormalities in CRH secretion have been documented in both the depression and manic phases of bipolar disorder (BPD). In the present study, we investigated genetic linkage between the CRH gene and BPD in 22 pedigrees. A highly informative, short tandem repeat (STR) polymorphism adjacent to the CRH gene on human chromosomal region 8q13 was used to examine linkage. Affected sibling pair (ASP) and the likelihood-based disequilibrium tests revealed nonsignificant values. We conclude that the CRH gene is not linked to BPD; if genes involved in the regulation of stress response are indeed linked to BPD, the search should be directed towards those that regulate CRH secretion or its effects on target tissues.

Bipolar Disorder↗

An integrated physical map of 18p11.2: a susceptibility region for bipolar disorder.

The reported linkage between bipolar disorder and a large pericentric portion of chromosome 18 has been replicated in an independent study. Further examination of this region showed that 18p11.2 had the greatest allele sharing in our pedigrees and increased sharing in other independently ascertained pedigree series permitting refinement of the region of significance. To facilitate positional cloning of a susceptibility gene, we used a combination of mapping reagents, including a subchromosomal somatic cell hybrid panel, a contig of clones in yeast artificial chromosomes (YAC), and a radiation hybrid (RH) panel, to construct a high resolution physical map of the region including sequence tag sites (STSs) and expressed sequence tags (ESTs). This approach generated the interlocus distance and order of 15 STSs and 16 ESTs including four novel transcripts, with an average of approximately 200 kb between loci, over a approximately 6-Mb region. This high resolution integrated map will be an important tool in providing loci for contig construction, and positional candidates for mutation screening.

Bipolar Disorder↗