11013
The transmembrane topology of Na ( + ) / H ( + ) exchanger NHE3 has been studied using in vitro transcription / translation of two types of fusion vectors designed to test membrane insertion properties of cDNA sequences encoding putative NHE3 membrane spanning domains ( msds ) .
 NHE3, NHE3
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 NHE3, NHE3