| Abstract: |
We have investigated whether the expression of hCG genes can be attributed to changes in the structure of the α- and βhCG genes, such as rearrangements, duplications, or methylation patterns. Various tissues and cell lines were studied: two term placentae, three trophoblastic tumor cell lines, two tumor cell lines ectopically producing α-subunit, normal cells not producing hCG or subunits, and a nonproducing malignancy. Gene structure was explored by restriction enzyme analysis and Southern blotting of DNA, using as probes 32P-labeled plasmids containing α- and βhCG cDNAs. Similarly, methylation was evaluated using the restriction enzymes Msp I, Hpa II, and Hha I, each sensitive to a different pattern of cytosine methylation. No structural changes were observed in α- and βhCG genes, although certain polymorphisms were observed. Analysis of methylation patterns revealed variation of the methylated cytosines; however, no clear correlation was seen between overall methylation or a specific pattern of methylation of these genes and their expression. Although specific methylated nucleotides of regulatory importance may not have been detected by our methods, we can still conclude that neither DNA structural alterations nor patterns of cytosine methylation appear to be major determinants of hCG expression. © 1985 by The Endocrine Society. |
| Keywords: |
human cell; methylation; neoplasms; gene expression; biological model; lung neoplasms; cell line; in vitro study; dna; genetic engineering; cell culture; diagnosis; peptide fragments; pregnancy; carcinoid; nucleic acid hybridization; lymphocytes; placenta; chorionic gonadotropin, beta subunit, human; trophoblastic neoplasms; chorionic gonadotropin; female genital system; endocrine system; cancer; human; female; priority journal; dna restriction enzymes; polymorphism (genetics); support, u.s. gov't, p.h.s.; glycoprotein hormones, alpha subunit; deoxyribonuclease hpaii
|
