Analysis of the Size of the Carcinoembryonic Antigen (CEA) Gene Family

Five members of the human CEA gene family [human pregnancy-specific β1-glycoprotein (PSβG), hsCGM1, 2, 3 and 4] have been isolated and identified through sequencing the exons containing their N-terminal domains. Sequence comparisons with published data for CEA and related molecules reveal the existence of highly-conserved gene subgroups within the CEA family. Together with published data eleven CEA family members have so far been determined. Apart from the highly conserved coding sequences, these genes also show strong sequence conservation in their introns, indicating a duplication of whole gene units during the evolution of the CEA gene family

The Human Pregnancy-Specific Glycoprotein Genes are Tightly Linked on the Long Arm of Chromosome 19 and are Coordinately Expressed

The pregnancy-specific glycoprotein (PSG) genes encode a group of proteins which are found in large amounts in placenta and maternal serum. In situ hybridization analyses of metaphase chromosomes reveal that all the human pregnancy-specific glycoprotein (PSG) genes are located on the long arm of chromosome 19 (19q13.2–13.3), overlapping the region containing the closely-related carcinoembryonic antigen (CEA) gene subgroup. Higher resolution analyses indicate that the PSG genes are closely linked within an 800kb SacII restriction endonuclease fragment. This has been confirmed through restriction endonuclease mapping and DNA sequence analyses of isolated genomic clones, which show that at least some of these genes are located in very close proximity. Further, these studies have helped to identify a new member of the PSG gene sub-family (PSG7). DNA/RNA hybridization analyses, using gene-specific oligonucleotide probes based on published sequences, showed that five from six PSG genes tested are coordinately transcribed in the placenta. Due to the close proximity of these genes and their coordinated expression pattern, common transcriptional regulatory elements may exist

Long-Range Chromosomal Mapping of the Carcinoembryonic Antigen (CEA) Gene Family Cluster

A long-range physical map of the carcinoembryonic antigen (CEA) gene family cluster, which is located on the long arm of chromosome 19, has been constructed. This was achieved by hybridization analysis of large DNA fragments separated by pulse-field gel electrophoresis and of DNA from human/rodent somatic cell hybrids, as well as the assembly of ordered sets of cosmids for this gene region into contigs. The different approaches yielded very similar results and indicate that the entire gene family is contained within a region located at position 19q13.1–q13.2 between the CYP2A and the D19S15/D19S8 markers. The physical linkage of nine genes belonging to the CEA subgroup and their location with respect to the pregnancy-specific glycoprotein (PSG) subgroup genes have been determined, and the latter are located closer to the telomere. From large groups of ordered cosmid clones, the identity of all known CEA subgroup genes has been confirmed either by hybridization using gene-specific probes or by DNA sequencing. These studies have identified a new member of the CEA subgroup (CGM8), which probably represents a pseudogene due to the existence of two stop codons, one in the leader and one in the N-terminal domain exons. The gene order and orientation, which were determined by hybridization with probes from the 5′ and 3′ regions of the genes, are as follows: cen/3′-CGM7-5′/3′-CGM2-5′/5′-CEA-3′/5′-NCA-3′/5′- CGM1-3′/3′-BGP-5′/3′-CGM9-5′/3′-CGM6-5′/5′-CGM8-3′/PSGcluster/qter

Carcinoembryonic Antigen Gene Family

The carcinoembryonic antigen (CEA) gene family belongs to the immunoglobulin supergene family and can be divided into two main subgroups based on sequence comparisons. In humans it is clustered on the long arm of chromosome 19 and consists of approximately 20 genes. The CEA subgroup genes code for CEA and its classical crossreacting antigens, which are mainly membrane-bound, whereas the other subgroup genes encode the pregnancy-specific glycoproteins (PSG), which are secreted. Splice variants of individual genes and differential post-translational modifications of the resulting proteins, e.g., by glycosylation, indicate a high complexity in the number of putative CEA-related molecules. So far, only a limited number of CEA-related antigens in humans have been unequivocally assigned to a specific gene. Rodent CEA-related genes reveal a high sequence divergence and, in part, a completely different domain organization than the human CEA gene family, making it difficult to determine individual gene counterparts. However, rodent CEA-related genes can be assigned to human subgroups based on similarity of expression patterns, which is characteristic for the subgroups. Various functions have been determined for members of the CEA subgroup in vitro, including cell adhesion, bacterial binding, an accessory role for collagen binding or ecto-ATPases activity. Based on all that is known so far on its biology, the clinical outlook for the CEA family has been reassessed

Structure, évolution et expression de gènes appartenant à la famille des "Pregnancy specific Beta1 glycoprotein"

Doctorat en sciences médicalesinfo:eu-repo/semantics/nonPublishe

Structure, évolution et expression de gènes appartenant à la famille des "Pregnancy specific Beta1 glycoprotein"

Doctorat en sciences médicalesinfo:eu-repo/semantics/nonPublishe

[Impurity photoconductivity in copper doped cadmium sulphide]

In a study of the spectral distribution of photoconductivity in CdS:Cu, it was found that information on the behaviour of impurity levels in the forbidden band could be obtained from charge transfer studies. The Cu dopant gives rise to three characteristic levels which, once populated, result in a Gaussian type contribution to the total photoconductivity. There is excellent correlation between the results obtained and luminescence data.Francai

Photoconductivité induite de CDS (CU). Effet de mémoire et localisation des niveaux accepteurs.

Thèse de doctorat -- Université catholique de Louvain, 196

Expression of human pregnancy specific beta 1 glycoprotein (PSG) genes during placental development.

Using gene-specific oligonucleotide probes, the expression of four pregnancy specific beta 1 glycoprotein (PSG) genes termed A, B, C-D and E (Streydio et al. 1988 and in press) and of some of their splice variants Ci, C and D were analysed during human placental development. Except for a stronger hybridization signal obtained at 9 weeks of gestation, which might be correlated to the development of the placenta, the relative amounts of the different PSG mRNAs showed little variation throughout pregnancy as revealed by Northern blots performed at 6, 13, 18 and 40 weeks of gestation. The expression of the different PSG genes does not seem to be developmentally regulated, in contrast to placental lactogen, used as a control, the expression of which is clearly correlated with the age of gestation. PSG D, A, E transcripts seem equally abundant, while PSG B expression was much lower. Moreover, the proportion of the PSG C-D variants resulting from alternative splicing remained constant during gestation.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe