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Targeted genomic integration of EGFP under tubulin beta 3 class III promoter and mEos2 under tryptophan hydroxylase 2 promoter does not produce sufficient levels of reporter gene expression
Author(s) -
Menzorov Aleksei G.,
Orishchenko Konstantin E.,
Fishman Veniamin S.,
Shevtsova Anastasia A.,
Mungalov Roman V.,
Pristyazhnyuk Inna E.,
Kizilova Elena A.,
Matveeva Natalia M.,
Alenitalia,
Bader Michael,
Rubtsov Nikolai B.,
Serov Oleg L.
Publication year - 2019
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.28981
Subject(s) - green fluorescent protein , biology , tph2 , transgene , reporter gene , tryptophan hydroxylase , promoter , microbiology and biotechnology , gene expression , gene , serotonergic , genetics , receptor , serotonin
Neuronal tracing is a modern technology that is based on the expression of fluorescent proteins under the control of cell type–specific promoters. However, random genomic integration of the reporter construct often leads to incorrect spatial and temporal expression of the marker protein. Targeted integration (or knock‐in) of the reporter coding sequence is supposed to provide better expression control by exploiting endogenous regulatory elements. Here we describe the generation of two fluorescent reporter systems: enhanced green fluorescent protein (EGFP) under pan‐neural marker class III β‐tubulin ( Tubb3 ) promoter and mEos2 under serotonergic neuron‐specific tryptophan hydroxylase 2 ( Tph2 ) promoter. Differentiation of Tubb3‐EGFP embryonic stem (ES) cells into neurons revealed that though Tubb3‐positive cells express EGFP, its expression level is not sufficient for the neuronal tracing by routine fluorescent microscopy. Similarly, the expression levels of mEos2‐TPH2 in differentiated ES cells was very low and could be detected only on messenger RNA level using polymerase chain reaction‐based methods. Our data shows that the use of endogenous regulatory elements to control transgene expression is not always beneficial compared with the random genomic integration.