The pENTR223.1 vectors are entry vectors for the Gateway cloning system (developed by LIfe Technologies - you can find more info about this system here: http://www.lifetechnologies.com/us/en/home/life-science/cloning/gateway-cloning.html).  The gene insert is actually inserted in between the two att sites in the vector such that the gene insert replaces the sequence between the att site (usually a death cassette) during recombinational cloning.  If you want to clone this gene insert into an expression vector, you can do so through recombinational cloning into a Gateway destination vector (you can find many of these through Life Technologies or through DNASU https://dnasu.org).  You can also do standard PCR-based cloning using gene-specific primers.  

Best way is to do PCR and amplify gene of interest from this vector using suitable primers and restriction sites clone in the preferred vector.