Amino acid variations resulting in functional and nonfunctional zebrafish P2X1 and P2X5.1 receptors

Abstract

Several zebrafish P2X receptors (zP2X 1 , zP2X 2 , and zP2X 5

NTPDase family in zebrafish: Nucleotide hydrolysis, molecular identification and gene expression profiles in brain, liver and heart

“…In fact, several studies have demonstrated the existence of duplicated genes in zebrafish (Amores et al, 1998;Rosemberg et al, 2007). Concerning purinergic signaling, it has been recently reported that the zebrafish family of ionotropic P2X receptors is comprised of nine members with two paralog copies of P2X 3 , P2X 4 , and P2X 5 (Low et al, 2008). The NTPDase7 ortholog was not detected in zebrafish, which lead us to hypothesize that its respective gene might not yet have been characterized or even that this member might have been lost from the zebrafish genome during evolution.…”

Molecular and functional properties of P2X receptors—recent progress and persisting challenges

“…In zebrafish, two paralogous P2X5 genes have been reported. zP2rx5.1 was mapped on chromosome 5, and zP2rx5.2 (also known as zP2rx514 or zP2rx8) is located on chromosome 15 [ 57 , 429 , 490 ]. The zP2rx5.1 receptor is the only zP2X receptor for which mRNA has been detected in embryonic skeletal muscle, whereas zP2rx5.2 mRNA, like other zP2X receptor mRNAs, was found in the nervous system [ 429 , 490 , 491 ].…”

“…zP2rx5.1 was mapped on chromosome 5, and zP2rx5.2 (also known as zP2rx514 or zP2rx8) is located on chromosome 15 [ 57 , 429 , 490 ]. The zP2rx5.1 receptor is the only zP2X receptor for which mRNA has been detected in embryonic skeletal muscle, whereas zP2rx5.2 mRNA, like other zP2X receptor mRNAs, was found in the nervous system [ 429 , 490 , 491 ]. Using morpholino-mediated zP2rx5.1 gene knockdown, it was demonstrated that the zP2rx5.1 receptor is necessary for the muscle responsiveness to ATP but is not essential for myogenesis during zebrafish embryonic development [ 490 ].…”

“…Subsequently, human and murine P2X6 receptor counterparts (originally designated as P2XM) have been identified in a search for novel p53-regulated genes [ 206 , 492 ]. Interestingly, no P2X6 ortholog has so far been found in zebrafish or any other non-mammalian species [ 490 ].…”

Evolution of P2X receptors

“…In general, all neurons fall into three groups—those expressing only one of the subunits or those expressing both 87. zP2X 1 and zP2X 5:1 receptors produced substantial currents when expressed by Xenopus oocytes, but the zP2X 2 receptor appeared to be nonfunctional 88. They also showed that embryonic skeletal muscle expressed only one P2X receptor, namely P2X 5.1 and that antisense knockdown of P2X 5.1 eliminated skeletal muscle responsiveness to ATP, although it did not prevent myogenesis.…”