JacoRen57 is a cluster AB mycobacteriophage that infects Mycobacterium smegmatis mc²155. We recently reported on the characterization of a putative promoter in JacoRen57 using an mCherry reporter construct. This promoter is present in a gap upstream of a gene that is present in all AB phages. In all cases, these are forward genes immediately following a long series of reverse genes. The genes are most frequently identified as a RecA-like DNA recombinases but also as RepA by bioinformatics. To further analyze this putative promoter and gene product, NWC Molecular Genetics students cloned the RecA-like DNA recombinase into an E. coli expression vector with a TVMV removable N-terminal His-tag. They expressed and we purified the tagged protein and are using it to immunize Balb/c mice. We plan to use the antiserum to confirm RecA-like DNA recombinase expression patterns when JacoRen57 infects M. smegmatis