Transcriptional activity of multiple copies of a subtelomerically located olfactory receptor gene that is polymorphic in number and location

We report here on the transcriptional activity of multiple copies of a subtelomerically located olfactory receptor (OR) gene, OR-A. Due to recent duplication events, both the copy number and chromosomal location of OR-A vary among humans. Sequence analyses of 180 copies of this gene, derived from 12 chromosome ends in 22 individuals, show that the main coding exon of all but one copy is an intact open reading frame with 0-5 predicted amino acid differences. We detected transcription of OR-A in both olfactory epithelium and testis tissue using RT-PCR amplification with primers designed on the basis of a computationally predicted gene structure. Two alternatively spliced forms of transcripts, one encoding an isoform with an extended N-terminus, were found in both tissues. A third transcript, derived from a second promoter, was also observed in testes. The start methionine is predicted in all transcripts to lie in an upstream exon rather than the main coding exon, as is typical for most other OR genes. By examining sequence variants among transcripts, we show that transcription of this gene occurs at multiple chromosomal locations. Our results lend credence to the idea that OR diversity could be generated in rearrangement-prone subtelomeric regions and show that polymorphism in subtelomeric regions could lead to individual-to-individual variation in the expressed repertoire of OR genes.

Histopathologic evaluation of proliferating cell nuclear antigen (PC10) in oral epithelial hyperplasias and premalignant lesions

As the therapeutic options for malignant lesions expand, early accurate diagnosis of premalignancy is becoming increasingly important in the concept of cancer prevention. Because it has been hypothesized that abnormal cell proliferation is related to subsequent malignant transformation, many proliferation markers such as proliferating cell nuclear antigen have been studied in a variety of malignant tumors. In oral surface epithelium, proliferating cell nuclear antigen activity is restricted to basal layers of normal squamous mucosa. In this preliminary study, 169 formalin-fixed, paraffin-embedded oral epithelial lesions, including 28 carcinomas in situ, 82 epithelial dysplasias, 21 epithelial atypia, and 38 typical epithelial hyperplasias, were studied with a monoclonal antibody, PC10, to determine whether proliferating cell nuclear antigen suprabasal expression correlated with premalignancy. The findings revealed that with progression of lesions toward malignancy, there was a significant predilection for basal/suprabasal staining pattern for proliferating cell nuclear antigen as compared with the strictly basal staining pattern seen in normal and benign epithelial conditions. One unexpected staining pattern, suprabasal positive stain only, was also noted mostly in reactive hyperplasia and dysplasia. The data suggested that a positive basal/suprabasal staining pattern for proliferating cell nuclear antigen is indicative of premalignancy in oral epithelial lesions.

A dynamin-like protein encoded by the yeast sporulation gene SPO15

The tightly centromere-linked gene SPO15 is essential for meiotic cell division in the yeast Saccharomyces cerevisiae. Diploid cells without the intact SPO15 gene product are able to complete premeiotic DNA synthesis and genetic recombination, but are unable to traverse the division cycles. Electron microscopy of blocked cells reveals a duplicated but unseparated spindle-pole body. Thus cells are unable to form a bipolar spindle. Sequence analysis of SPO15 DNA reveals an open reading frame that predicts a protein of 704 amino acids. This protein is identical to VPS1, a gene involved in vacuolar protein sorting in yeast which has significant sequence homology (45% overall, 66% over 300 amino acids) to the microtubule bundling-protein, dynamin. The SPO15 gene product expressed in Escherichia coli can be affinity-purified with microtubules. SPO15 encodes a protein that is likely to be involved in a microtubule-dependent process required for the timely separation of spindle-pole bodies in meiosis.

Evoked potential changes during ethanol withdrawal in rats

We have recently observed an increase in central nervous system excitability during intoxication and alcohol withdrawal in alcoholics. Our present results demonstrate a similar phenomenon in rats. The hyper-excitability caused by ethanol withdrawal is still present subsequent to the overt behavioral symptoms of withdrawal.