Sex-specific splicing of Z- and W-borne nr5a1 alleles suggests sex determination is controlled by chromosome conformation
Date
2022
Authors
Zhang, Xiuwen
Wagner, Susan
Holleley, Clare E.
Deakin, Janine
Matsubaraa, Kazumi
Deveson, Ira
O’Meally, Denis
Patel, Hardip
Ezaz, Tariq
Li, Zhao
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National Academy of Sciences (USA)
Abstract
Pogona vitticeps has female heterogamety (ZZ/ZW), but the master sex-determining gene is unknown, as it is for all reptiles. We show that nr5a1 (Nuclear Receptor Subfamily 5 Group A Member 1), a gene that is essential in mammalian sex determination, has alleles on the Z and W chromosomes (Z-nr5a1 and W-nr5a1), which are both expressed and can recombine. Three transcript isoforms of Z-nr5a1 were detected in gonads of adult ZZ males, two of which encode a functional protein. However, ZW females produced 16 isoforms, most of which contained premature stop codons. The array of transcripts produced by the W-borne allele (W-nr5a1) is likely to produce truncated polypeptides that contain a structurally normal DNA-binding domain and could act as a competitive inhibitor to the full-length intact protein. We hypothesize that an altered configuration of the W chromosome affects the conformation of the primary transcript generating inhibitory W-borne isoforms that suppress testis determination. Under this hypothesis, the genetic sex determination (GSD) system of P. vitticeps is a W-borne dominant female-determining gene that may be controlled epigenetically.
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Keywords
reptile sex determination, nr5a1, chromosome conformation, sex-specific splicing
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PNAS - Proceedings of the National Academy of Sciences of the United States of America
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Journal article
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2099-12-31
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