(A) Alpha-lactalbumin (alpha-LA)-like proteins modify the activity of N-acetyl-glucosaminide beta 1-4 galactosyltransferase and their expression is regulated by hormones. We have isolated and sequenced entire mammary gland alpha-LA gene, including its 5'-flanking sequences. The gene sequences were compared with chicken lysozome gene, since it was proposed that the two genes have arisen from a common ancestral gene. These studies show: 1) alpha-LA and lysozome genes contain 3 introns at similar positions. The first three exons show high nucleotide homologies; 2) 5'-flanking sequence of alpha-LA gene has several identical short repeat sequences. Some of these sequences resemble the concensus sequences which bind hydrocortisone and progesterone receptors which modulate the expression of this gene; and 3) the fourth exon of alpha-LA, which partly codes for the C-terminal residues of the protein, essential for its interaction with galactosyltransferase, is markedly different from the corresponding exon of lysozome gene and is preceded by two (TG) repeats-(TG)21 and (TG)24. It is suggested that the 4th exon of alpha-LA coding for a new functional unit might have replaced the DNA region of primordial lysozome gene and led to a protein with a new function. (B) Rat whey phosphoprotein (Wp) has a double domain structure with striking homologies to a protease inhibitor. Wp-gene expression is regulated by the same set of hormones as the alpha-LA gene. Rat Wp-gene has been isolated and its full sequence is nearing completion. The gene structure and nucleotide sequences show that: a) there are three intervening sequences in the entire gene which is 2.5 kb in length; b) second and third exons code for first and second domains of the protein, respectively; and c) first and the third intervening sequences encompassing the second and third exons, have several repeat and inverted repeat sequences.

Agency
National Institute of Health (NIH)
Institute
Division of Cancer Biology And Diagnosis (NCI)
Type
Intramural Research (Z01)
Project #
1Z01CB008220-04
Application #
4691817
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
4
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Cancer Biology and Diagnosis
Department
Type
DUNS #
City
State
Country
United States
Zip Code