2026-09-15T18:12:08Zhttps://gredos.usal.es/oai/request

oai:gredos.usal.es:10366/1571142025-04-30T19:41:19Zcom_10366_4028com_10366_3947com_10366_3946com_10366_3823col_10366_4029

Sacristán Martín, María Paz Gutiérrez de Diego, Juana Bonilla, Magdalena Martín Zanca, Dionisio Protooncogén trk A Clonación molecular [EN] The trkA proto-oncogene encodes a high-affinity NGF receptor that is essential for the survival, differentiation and maintenance of many neural and non-neural cell types. Altered expression of the trkA gene or trkA receptor malfunction have been implicated in neurode-generation, tumor progression and oncogenesis. We have cloned and characterized the 5' region of the mouse trkA gene and have identified its promoter. trkA promoter sequences are GC-rich, lack genuine TATA or CAAT boxes, and are contained within a CpG island which extends over the entire first coding exon. The mouse trkA transcription start site is located 70/71 bp upstream to the AUG translation initiation codon. Sequence analysis showed that the gene encoding the insulin receptor-related receptor, IRR, is located just 1.6 kbp upstream to the trkA gene and is transcribed in the opposite direction. We have used trkA-CAT transcriptional fusions to study trkA promoter function in transient transfection experiments. RNase protection assays and CAT protein ELISA analyses showed that a 150 bp long DNA segment, immediately upstream to the start site, is sufficient to direct accurate transcription in trkA-expressing cells. Dissection of this fragment allowed us to identify a 13 bp cis-regulatory element essential for both promoter activity and cell-type specific expression. Deletion of this 13 bp segment as well as modification of its sequence by site-directed mutagenesis led to a dramatic decline in promoter activity. Gel mobility shift assays carried out with double-stranded oligonucleotides containing the 13 bp element revealed several specific DNA-protein complexes when nuclear extracts from trkA-expressing cells were used. Supershift experiments showed that the Sp1 transcription factor was a component of one of these complexes. Our results identify a minimal trkA gene promoter, located very close to the transcription start site, and define a 13 bp enhancer within this promoter sequence. 2024-04-04 2024-04-04 1999 info:eu-repo/semantics/article Sacristán, M. P., de Diego, J. G., Bonilla, M., & Martín-Zanca, D. (1999). Molecular cloning and characterization of the 5′ region of the mouse trkA proto-oncogene. Oncogene, 18(42), 5836-5842. 0950-9232 http://hdl.handle.net/10366/157114 10.1038/sj.onc.1202963 1476-5594 eng https://doi.org/10.1038/SJ.ONC.1202963 DGICYT (PM91-0005 and PB94-1104) European Union Programs (BMH2-CT96-0010 and BIO4-CT96-0285) http://creativecommons.org/publicdomain/zero/1.0/ info:eu-repo/semantics/openAccess CC0 1.0 Universal nature.com