THE INFLUENCE OF TEMPERATURE ON MESSENGER-RNA LEVELS FOR MUSCLE CONTRACTILE PROTEIN AND A PROTOONCOGENE ASSOCIATED WITH CELL-DIVISION IN ATLANTIC SALMON (SALMO-SALAR L)
Tw. Matschak et Nc. Stickland, THE INFLUENCE OF TEMPERATURE ON MESSENGER-RNA LEVELS FOR MUSCLE CONTRACTILE PROTEIN AND A PROTOONCOGENE ASSOCIATED WITH CELL-DIVISION IN ATLANTIC SALMON (SALMO-SALAR L), Canadian journal of fisheries and aquatic sciences, 53(2), 1996, pp. 408-413
In Atlantic salmon (Salmo salar L.) embryos, an increase in temperatur
e from 5 to 8 or 11 degrees C causes, by the time of hatching, an incr
ease in myofibrillar protein content and a reduction in nuclear prolif
eration when compared with embryos raised at lower temperatures. This
implies a shift in emphasis during embryonic development from nuclear
hyperplasia to contractile protein accretion at higher temperatures. T
he steady-state mRNA levels of proteins indicative of these processes
were investigated. The proteins were actin, as a measure for myofibril
lar protein, and cellular myc, as a measure for nuclear proliferation.
Additionally a probe for myosin heavy chain was used. The mRNA levels
for myofibrillar protein were not increased at the higher temperature
, thus suggesting temperature-dependent translational or post-translat
ional control. Actin and myosin heavy chain mRNA responses differed, s
upporting the existence of temperature-dependent myosin heavy chain is
oforms. The presence of c-myc mRNA in embryonic Atlantic salmon was sh
own. The mRNA level of this nuclear proliferation marker was decreased
at higher temperatures and could be related to histological data on n
uclear numbers in embryonic salmon muscle.