maltose maltose glucose glucose (glucose-glucose) intracellular maltose MalE transport proteins (amylomaltose) Much like the Lac operon, the products of the Mal operon are induced when maltose is added to cells. Thus maltose acts as an inducer cell mass amount MalE maltose time When mutants that affect the regulation of the Mal operon were isolated, the most common type consisted of uninducible mutations in a gene known as MalT. We can apply dominance tests and cis-trans tests to Malt mutations with the following results maltase activity maltose +maltose Interpretation Maltose induces Mal operon MalT Malt is uninducible MalT-/F MalT+ Malt is recessive MalT- Ma@*/F MaIT+ MalA MalT is trans-acting MaIT- Mal@-/F MaIT+ Mala+ From this table it looks as if the MalT trait is not expressed either in cis or in trans Because MalT is recessive, it makes more sense to consider the properties of the dominant Malt allele in the cis/trans test. viewed in this way the malt trait is expressed in both cis and trans and therefore MalT is considered to be trans-actingmaltose maltose glucose + glucose (glucose-glucose) intracellular maltose MalQ transport proteins (amylomaltase) Much like the Lac operon, the products of the Mal operon are induced when maltose is added to cells. Thus, maltose acts as an inducer. log amount + maltose cell mass MalQ time When mutants that affect the regulation of the Mal operon were isolated, the most common type consisted of uninducible mutations in a gene known as MalT. We can apply dominance tests and cis-trans tests to MalTmutations with the following results: maltase activity –maltose +maltose Interpretation Mal+ – + Maltose induces Mal operon MalT– – – MalT–is uninducible MalT–’/ F MalT+ – + MalT–is recessive MalT– MalQ+/ F’MalT+ MalQ– – + MalT is trans-acting MalT– ’ MalQ–/ F MalT+ MalQ+ – + From this table it looks as if the MalT– trait is not expressed either in cis or in trans. Because MalT– is recessive, it makes more sense to consider the properties of the dominant MalT+ allele in the cis/trans test. Viewed in this way, the MalT+ trait is expressed in both cis and trans and therefore MalT is considered to be trans-acting