Abstract

Our earlier in situ hybridisation studies have shown heterogeneous expression of milk protein genes. At some sites, a sharp demarcation of mRNA expression is seen at the basement membrane between 'active' and 'inactive' tissue, while at other nearby sites, a reciprocal gradient of mRNA expression about 10 cells wide is seen. The alveoli in these latter 'inactive' sites contain leucocytes which indicates that they have been 'inactive' longer than the former. This suggests a factor could be diffusing between 'inactive' and 'active' tissues and influencing milk gene expression. We used a consensus oligomer corresponding to the linkers between the fingers of zinc finger DNA binding proteins in a polymerase chain reaction performed on cDNA from 'active' versus 'inactive' mammary mRNA. Differences and similarities were observed in the sizes of the DNA products from each sample. Several of the bands present in the 'active' cDNA and absent from the 'inactive' cDNA were cloned and some were found to have homologies to zinc finger and other DNA binding proteins. It is possible that we have partially isolated a component of the pathway that maintains lactation.

AJ, Molenaar, DR Musgrave, and RJ Wilkins

Proceedings of the New Zealand Society of Animal Production, Volume 54, , 303-306, 1994