Two Na,K-ATPase beta 2 subunit isoforms are differentially expressed within the central nervous system and sensory organs during zebrafish embryogenesis.
We have identified cDNAs encoding a second zebrafish ortholog of the human Na,K-ATPase beta 2 subunit. The beta 2b cDNA encodes a 292 amino acid-long polypeptide with 74% identity to the previously characterized zebrafish beta 2a subunit. By using a zebrafish meiotic mapping panel, we determined that the beta 2b gene (atp1b2b) was tightly linked to markers on linkage group 5, whereas the beta 2a gene was located on linkage group 23. In situ hybridization analysis shows that in developing zebrafish embryos, atp1b2a and atp1b2b are predominantly expressed in the nervous system. beta 2a transcripts were abundantly expressed throughout brain as well as spinal cord neurons and lateral line ganglia. In contrast, beta 2b mRNA expression was primarily detected in sensory organs, including retina, otic vesicles, and lateral line neuromast cells. These results suggest that the beta 2a and beta 2b genes play distinct roles in developing brain and sensory organs, and raise the possibility that the functions encoded by the single mammalian beta 2 gene may be partitioned between the two zebrafish beta 2 orthologs.
Rajarao
Johannes R
JR
Department of Pharmacology, Penn State College of Medicine, Hershey, PA 17033, USA.
Canfield
Victor A
VA
Loppin
Benjamin
B
Thisse
Bernard
B
Thisse
Christine
C
Yan
Yi-Lin
YL
Postlethwait
John H
JH
Levenson
Robert
R
D000818:Animals; D002490:Central Nervous System / Q000196:embryology* / Q000201:enzymology; D002874:Chromosome Mapping; D018076:DNA, Complementary / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000648:ultrastructure; D019143:Evolution, Molecular; D017950:Ganglia, Sensory / Q000196:embryology / Q000201:enzymology; D018507:Gene Expression Regulation, Developmental; D005796:Genes; D008040:Genetic Linkage; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D009024:Morphogenesis; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D009474:Neurons / Q000201:enzymology; D009928:Organ Specificity; D021122:Protein Subunits; D012333:RNA, Messenger / Q000096:biosynthesis; D012679:Sense Organs / Q000196:embryology* / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
D018076:DNA, Complementary; D007527:Isoenzymes; D009419:Nerve Tissue Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D000254:Sodium-Potassium-Exchanging ATPase