You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Gene"].

Please return the output as a JSON object of the format: {"Gene": ["SSX", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Molecular cloning of the cDNA for human TrkC (NTRK3), chromosomal assignment, and evidence for a splice variant. TrkC is a receptor tyrosine kinase that is activated by neurotrophin-3, a factor important in the development of certain areas of the central nervous system. We have cloned and sequenced the human trkC cDNA and found that the predicted amino acid sequence is 97 to 98% homologous to the rat and porcine trkC sequences, respectively. The rat trkC has several isoforms due to alternative splicing in the tyrosine kinase domain. We cloned one human splice variant that has a nucleic acid sequence identical to the rat isoform with an insert of 14 amino acids. The human trkC cDNA also has a (CGG)n repeat in the 5'-untranslated region. This sequence was not highly polymorphic in that 79 of 80 chromosomes examined had eight repeats, while 1 chromosome had four repeats. By PCR analysis of a somatic cell hybrid panel and fluorescence in situ hybridization with the cDNA clone, human trkC was mapped to chromosome 15q24-q25.
{"Gene": ["receptor tyrosine kinase", "tyrosine kinase domain", "neurotrophin-3", "NTRK3", "TrkC", "trkC"]}