Abstract
Alternative splicing of primary transcripts from the calcitonin/α calcitonin gene-related peptide (αCGRP) gene result in mature mRNAs encoding either calcitonin or αCGRP. We have produced sequence-specific, synthetic, biotinylated oligodeoxynucleotide probes that recognize calcitonin (exon 4), and αCGRP (exon 6) sequences as well as sequences common to both splice variants (exon 3) of this gene. Probes to exons 4 and 3 revealed strong cytoplasmic signals in rat parafollicular cells. In addition, a punctate nuclear signal was obtained with these probes. The αCGRP-specific (exon 6) probe resulted in weak cytoplasmic labelling of parafollicular cells, but produced a punctate nuclear labelling similar to that seen with the exon 4 and 3 probes. RNase digestion removed all the cytoplasmic and nuclear signals obtained with all probes. Hybridization with a thyroglobulin-specific probe failed to label parafollicular cells. A control (human enterovirus) probe yielded negative results, while a probe to rat somatostatin produced cytoplasmic labelling of a small subpopulation of parafollicular cells. Finally, a probe specific for βCGRP mRNA labelled most, if not all, parafollicular cells. Fluorescent alkaline phosphatase development of in situ hybridizations could be combined with indirect immunofluorescence for CGRP. Analysis by fluorescence and confocal microscopy revealed that CGRP immunoreactive cells contained calcitonin, αCGRP and βCGRP hybridization signals. Our results demonstrate that all three genes may be simultaneously expressed by thyroid parafollicular cells and show that synthetic biotinylated oligonucleotide probes can be used for highly precise localizations of primary transcripts in the nuclei of these cells. The punctate distribution of the nuclear hybridizations may be correlated to the locations of spliceosomes and/or nuclear transport routes.
Original language | English |
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Pages (from-to) | 19-24 |
Journal | Histochemistry and Cell Biology |
Volume | 103 |
DOIs | |
Publication status | Published - Jan 1995 |
Externally published | Yes |
Bibliographical note
Acknowledgements Grant support is gratefully acknowledged from the Danish National Research Foundation, Danish MRC andCancer Societies and from the Danish Biotechnology Programme (Research Centre for Medical Biotechnology). E. van Lieshout
was supported by a Dutch-Danish exchange programme.