TY - JOUR
T1 - Molecular control of glutamine synthetase expression in the developing retina tissue
AU - Vardimon, Lily
AU - Ben‐dror, Iris
AU - Havazelet, Nadav
AU - Fox, Lyle E.
PY - 1993/4
Y1 - 1993/4
N2 - Glutamine synthetase is a differentiation marker of the neural retina, whose expression is restricted to Müller glia cells, is inducible by glucocorticoids and is dependent on tissue development. The retina tissue acquires the competence to express GS in response to glucocorticoids with development, although the level of hormone binding activity in the cells does not alter with age. Using CAT constructs that are controlled by “simple GRE” promoters we demonstrated that glucocorticoid receptor transcription activity in retina cells increases with development. The increase in receptor activity correlates directly with the increase in inducibility of the glutamine synthetase gene and inversely with the rate of retina cell proliferation. At early developmental ages, when retina cells are still proliferating, the glucocorticoid receptor is transcriptionally inactive and glutamine synthetase expression cannot be induced. Receptor activity increases progressively with development and by day 12, when cell proliferation ceases, competence for glutamine synthetase induction is high. This competence for glutamine synthetase induction can be repressed by overexpressing the oncogene v‐src, which stimulates retina cell proliferation. We discuss possible mechanisms for developmental‐dependent modulation of glucocorticoid receptor transcriptional activity. © 1993 wiley‐Liss, Inc.
AB - Glutamine synthetase is a differentiation marker of the neural retina, whose expression is restricted to Müller glia cells, is inducible by glucocorticoids and is dependent on tissue development. The retina tissue acquires the competence to express GS in response to glucocorticoids with development, although the level of hormone binding activity in the cells does not alter with age. Using CAT constructs that are controlled by “simple GRE” promoters we demonstrated that glucocorticoid receptor transcription activity in retina cells increases with development. The increase in receptor activity correlates directly with the increase in inducibility of the glutamine synthetase gene and inversely with the rate of retina cell proliferation. At early developmental ages, when retina cells are still proliferating, the glucocorticoid receptor is transcriptionally inactive and glutamine synthetase expression cannot be induced. Receptor activity increases progressively with development and by day 12, when cell proliferation ceases, competence for glutamine synthetase induction is high. This competence for glutamine synthetase induction can be repressed by overexpressing the oncogene v‐src, which stimulates retina cell proliferation. We discuss possible mechanisms for developmental‐dependent modulation of glucocorticoid receptor transcriptional activity. © 1993 wiley‐Liss, Inc.
KW - Embryonic development
KW - Glucocorticoid receptor
KW - Glutamine synthetase
KW - Müller glia
KW - Neural retina
KW - v‐src
UR - http://www.scopus.com/inward/record.url?scp=0027325556&partnerID=8YFLogxK
U2 - 10.1002/aja.1001960410
DO - 10.1002/aja.1001960410
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AN - SCOPUS:0027325556
SN - 1058-8388
VL - 196
SP - 276
EP - 282
JO - Developmental Dynamics
JF - Developmental Dynamics
IS - 4
ER -