Tyrosinase activity (TH, DO, PAGE-defined isozymes) and melanin production in regenerating hairbulb melanocytes of lethal yellow (Ay/a), black (a/a), agouti (AwJ/AwJ/) and albino (a/a/c2J/c2J) mice (C57BL/6J).
We compared tyrosinase activity (TH, DO, and native PAGE-defined isozymes) and melanin production in particulate and soluble fractions of hairbulb melanocytes of lethal yellow (Ay/a C/C), nonagouti black (a/a C/C), and albino (a/a c2J/c2J) of 3-, 6-, 9-, and 12-day regenerating hairbulbs. With respect to tyrosine hydroxylase (TH) and dopa oxidase (DO) activities, Ay/a melanocytes possessed only 25-35% of the activity of a/a; there were no genotype differences in either the subcellular distribution of activity in soluble and particulate fractions or in the relative increases of activity over the 12-day developmental period. TH data on wild-type agouti (AwJ/AwJ) mice over the 3-11 day regeneration interval showed an activity intermediate between that of a/a and Ay/a; the rate of TH increase reflected black and yellow phases of the agouti hair cycle. Analyses of the number and densities of dopa-sensitive bands following native PAGE of 3-, 6-, 9-, and 12-day hairbulb fractions of a/a and Ay/a mice suggested stage-dependent patterns. A comparison of rates and amounts of melanin production in 3-, 6-, 9-, and 12-day fractions showed consistent melanin production in Ay/a to be 10-20% that of a/a; however, fold increases in melanin production over the four stages were similar between genotypes. Overall, tyrosinase activity data support the notion that agouti locus modification of tyrosinase activity is a graded or quantitative rather than a qualitative phenomenon.
Granholm
N H
NH
Department of Biology and Microbiology, South Dakota State University, Brookings 57007.
Opbroek
A J
AJ
Harvison
G A
GA
Kappenman
K E
KE
D000818:Animals; D004295:Dihydroxyphenylalanine / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005838:Genotype; D006197:Hair / Q000502:physiology*; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008543:Melanins / Q000096:biosynthesis*; D008544:Melanocytes / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D014442:Monophenol Monooxygenase / Q000302:isolation & purification / Q000378:metabolism*; D012038:Regeneration; D013045:Species Specificity
D007527:Isoenzymes; D008543:Melanins; D004295:Dihydroxyphenylalanine; D014442:Monophenol Monooxygenase