Mapping and genomic characterization of the gene encoding diacylglycerol kinase gamma (DAGK3): assessment of its role in dominant optic atrophy (OPA1)

Comparative analysis of gene expression for convergent evolution of camera eye between octopus and human

Although the camera eye of the octopus is very similar to that of humans, phylogenetic and embryological analyses have suggested that their camera eyes have been acquired independently. It has been known as a typical example of convergent evolution. To study the molecular basis of convergent evolution of camera eyes, we conducted a comparative analysis of gene expression in octopus and human camera eyes. We sequenced 16,432 ESTs of the octopus eye, leading to 1052 nonredundant genes that have matches in the protein database. Comparing these 1052 genes with 13,303 already-known ESTs of the human eye, 729 (69.3%) genes were commonly expressed between the human and octopus eyes. On the contrary, when we compared octopus eye ESTs with human connective tissue ESTs, the expression similarity was quite low. To trace the evolutionary changes that are potentially responsible for camera eye formation, we also compared octopus-eye ESTs with the completed genome sequences of other organisms. We found that 1019 out of the 1052 genes had already existed at the common ancestor of bilateria, and 875 genes were conserved between humans and octopuses. It suggests that a larger number of conserved genes and their similar gene expression may be responsible for the convergent evolution of the camera eye.

Molecular biologic characteristics of seven new cell lines of squamous cell carcinomas of the head and neck and comparison to fresh tumor tissue

BACKGROUND

Squamous cell carcinoma (SCC) is the most frequent malignant tumor of the upper aerodigestive tract. Cell lines of these tumors facilitate the investigation of various tumor biological parameters. This study was conducted to compare molecular biologic characteristics between cell lines and fresh tumor tissue.

METHODS

In seven SCC-derived cell lines, cytokeratin 5/6 and cytokeratin 19 expression, DNA content, chromosome aberrations and tumorigenicity were assessed in nude rats. Unbalanced numerical and structural chromosomal aberrations were investigated by comparative genomic hybridization (CGH), and results were compared to those obtained in fresh tumor tissues of the same patients.

RESULTS

All cell lines expressed cytokeratins 5/6 and 19, indicating their epidermoid origin. Tumor growth after transplantation into nude rats occurred in five of seven cell lines. Routine histology and immunohistochemical examinations confirmed SCC. Aneuploidy was detected in all cell lines, with a 2c deviation index ranging from 1.9 through 9.5 and a 5c exceeding rate ranging from 2.6 through 36.7%. The most frequent chromosomal aberrations in cell lines were overrepresentations of chromosomal material on chromosomes 15q, 7p (5 cases each), 3q, 5p (4 cases each), and 11q and 17q (3 cases each) and losses of chromosomal material on chromosomes 3p, 18q (3 cases each), and 19p and 7q (2 cases each). Comparing these results to CGH analysis of fresh tumor tissue from the same patients, overrepresentations of chromosomal material on 10q, 20q and 21q, along with loss of chromosomal material on 4q was detected more frequently in primary tumors, whereas overrepresentations on 7p and loss of chromosomal material on 7q were more frequently detected in cell lines. Nevertheless, there was a high degree of similarity of chromosomal alterations in cell lines and corresponding fresh tumor tissue.

CONCLUSION

The data suggest a high degree of genetic similarity between tumor cells of cell lines and the tumors from which they were derived. Therefore, these cell lines can serve as an accurate model to investigate cell biology of SCC in vitro.

A new locus for a dominant form of multinodular goiter on 3q26.1-q26.3

A mass screening program for congenital hypothyroidism has markedly improved prognosis of children with congenital hypothyroidism and also revealed several cases with unknown pathogenesis. We here report two independent Japanese multigeneration families with multinodular goiter (MNG) with euthyroidism and with high TSH. The propositi, 3- and 8-year-old girls in two families, were found during a mass screening. An autosomal dominant pattern of inheritance was suggested in both families. The clinical examinations suggested impaired hormonogenesis but discarded known defects in iodine transport, organification, deficiency of hydrogen peroxide, and thyroid peroxidase. Linkage analysis of the two families including 10 members each using 343 microsatellite markers mapped a single locus independently at D3S1618 (theta = 0) on 3q26.1-q26.3 with a two-point LOD score 3.62 (1.81 for each family) and multipoint LOD score of 3.61 (1.80 for each family). Haplotype inspection delimited an 18-cM interval between D3S1565 and D3S3686.

Properties and functions of diacylglycerol kinases

Diacylglycerol kinases (DGKs) phosphorylate the second-messenger diacylglycerol (DAG) to phosphatidic acid (PA). The family of DGKs is well conserved among most species. Nine mammalian isotypes have been identified, and are classified into five subgroups based on their primary structure. DGKs contain a conserved catalytic domain and an array of other conserved motifs that are likely to play a role in lipid-protein and protein-protein interactions in various signalling pathways dependent on DAG and/or PA production. DGK is therefore believed to be activated at the (plasma) membrane where DAG is generated. Some isotypes are found associated with and/or regulated by small GTPases of the Rho family, presumably acting in cytoskeletal rearrangements. Others are (also) found in the nucleus, in association with other regulatory enzymes of the phosphoinositide cycle, and have an effect on cell cycle progression. Most DGK isotypes show high expression in the brain, often in distinct brain regions, suggesting that each individual isotype has a unique function.

Clinical heterogeneity in autosomal dominant optic atrophy in two 3q28-qter linked central Illinois families

PURPOSE

To examine the clinical and genetic heterogeneity of autosomal dominant optic atrophy among two unrelated central Illinois families.

METHODS

Forty-three individuals from two pedigrees had complete eye examinations. Linkage analysis was performed with microsatellite markers from the region 3q28-29.

RESULTS

Visual acuity in 21 affected individuals ranged from 20/25 to 20/800. Vision loss was more severe in males than females (P = 0.02). Color vision testing revealed generalized dyschromatopsia. Both visual acuity and color vision deteriorated with age. Linkage was established to chromosome 3q28-29 (LODmax = 4.68 for D3S2305).

CONCLUSION

Autosomal dominant optic atrophy linked to chromosome 3q28-29 shows intrafamilial phenotypic variation as well as sex-influenced severity in two Midwestern families.

Gene targets related to phospholipid and fatty acid metabolism in schizophrenia and other psychiatric disorders: an update

Phospholipids make up about 60% of the brain's dry weight and play key roles in many brain signal tranduction mechanisms. A recent review(1)identified the increasing evidence that abnormal phospholipid and related fatty acid metabolism may contribute to illnesses such as schizophrenia, bipolar disorder, depression and attention deficit hyperactivity disorder. This current paper reviews the main pathways of phospholipid metabolism, emphasizing the role of phospholipases of the A2 in signal tranduction processes. It also updates the chromosomal locations of regions likely to be involved in these disorders, and relates these to the known locations of genes directly or indirectly involved in phospholipid and fatty acid metabolism.