RADIOAUTOGRAPHIC VISUALIZATION OF THE INCORPORATION OF GALACTOSE-3H AND MANNOSE-3H BY RAT THYROIDS IN VITRO IN RELATION TO THE STAGES OF THYROGLOBULIN SYNTHESIS
Open Access
- 1 November 1969
- journal article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 43 (2), 289-311
- https://doi.org/10.1083/jcb.43.2.289
Abstract
Rat thyroid lobes incubated with mannose-(3)H, galactose-(3)H, or leucine-(3)H, were studied by radioautography. With leucine-(3)H and mannose-(3)H, the grain reaction observed in the light microscope is distributed diffusely over the cells at 5 min, with no reaction over the colloid. Later, the grains are concentrated towards the apex, and colloid reactions begin to appear by 2 hr. With galactose-(3)H, the reaction at 5 min is again restricted to the cells but it consists of clumped grains next to the nucleus. Soon after, grains are concentrated at the cell apex and colloid reactions appear in some follicles as early as 30 min. Puromycin almost totally inhibits incorporation of leucine-(3)H and mannose-(3)H, but has no detectable effect on galactose-(3)H incorporation during the 1st hr. Quantitation of electron microscope radioautographs shows that mannose-(3)H label localizes initially in the rough endoplasmic reticulum, and by 1-2 hr much of this reaction is transferred to the Golgi apparatus. At 3 hr and subsequently, significant reactions are present over apical vesicles and colloid, while the Golgi reaction declines. Label associated with galactose-(3)H localizes initially in the Golgi apparatus and rapidly transfers to the apical vesicles, and then to the colloid. These findings indicate that mannose incorporation into thyroglobulin precursors occurs within the rough endoplasmic reticulum; these precursors then migrate to the Golgi apparatus, where galactose incorporation takes place. The glycoprotein thus formed migrates via the apical vesicles to the colloid.Keywords
This publication has 41 references indexed in Scilit:
- AN ARTEFACT IN RADIOAUTOGRAPHY DUE TO BINDING OF FREE AMINO ACIDS TO TISSUES BY FIXATIVESThe Journal of cell biology, 1967
- [Elaboration of glycoproteins in the Golgi apparatus of the liver cells in rats; radioautographic study by electron microscopy after injection of galactose-3H].1966
- GLYCOPROTEIN BIOSYNTHESIS - STUDIES ON THYROGLOBULIN - CHARACTERIZATION OF A PARTICULATE PRECURSOR AND RADIOISOTOPE INCORPORATION BY THYROID SLICES AND PARTICLE SYSTEMS1966
- A function of the Golgi apparatus in polysaccharide synthesis and transport in the root-cap cells of wheatBiochemical Journal, 1966
- BIOSYNTHESIS OF THYROGLOBULIN .3. INTRACELLULAR LOCALIZATION AND PROPERTIES OF LABELED THYROID PROTEINS1965
- BIOSYNTHESE IODATION ET HETEROGENEITE DE LA THYROGLOBULINE1965
- BIOSYNTHESIS OF THYROGLOBULIN .2. ROLE OF SUBUNITS IODINATION AND RIBONUCLEIC ACID SYNTHESIS1965
- SYNTHESIS OF COMPLEX CARBOHYDRATES IN THE GOLGI REGION, AS SHOWN BY RADIOAUTOGRAPHY AFTER INJECTION OF LABELED GLUCOSEThe Journal of cell biology, 1964
- HIGH-RESOLUTION AUTORADIOGAPHYThe Journal of cell biology, 1962
- CARBOHYDRATES IN THYROGLOBULIN AND THE LENS CAPSULECanadian Journal of Biochemistry and Physiology, 1955