Analysis of the gene family encoding lipases in Candida rugosa by competitive reverse transcription-PCR

Synthesis of multiple extracellular lipases in Candida rugosa has been demo nstrated. However, it is difficult to characterize the expression spectrum of lip genes, since the sequences of the lip multigene family are very clos ely related. A competitive reverse transcription-PCR assay was developed to quantify the;expression of lip genes. In agreement with the protein profil e, the abundance of lip mRNAs was found to be tin decreasing order) lip1, l ip3, lip2, lip5, and lip4. To analyze the effects of different culture cond itions, the transcript concentrations for these nRNA species were normalize d relative to the values for gpd, encoding glyceraldehyde-3-phosphate dehyd rogenase. In relative terms, lip1 and lip3 were highly and constitutively e xpressed (about 10(5) molecules per mu g of total RNA) whereas the other in ducible lip genes, especially lip4 showed significant changes in mRNA expre ssion under different culture conditions. These results indicate that diffe rential transcriptional control of lip genes results in multiple forms of l ipase proteins.