Modulation of sterol regulatory element binding protein-2 in response to rapid follicle development in chickens.
We investigated the expression profiles of sterol regulatory element binding proteins (SREBPs) and their related genes in chicken developing follicle membranes, from the small white follicle (SWF) stage to the Follicle 1 (F1) stage. Expression of SREBP-2 was significantly increased in the rapid stages of follicle development, however, no significant change in SREBP-1 mRNA expression was observed during follicle development. Immunoreactive SREBP-2 protein levels isolated from nuclear extracts in rapid growth stages, particularly in Follicle 2, were higher than those in SWF and small yellow follicle (SYF). In contrast, SREBP-1 immunoreactive protein levels were only slightly changed over all stage of follicle development. 3-Hydroxy-3-methylglutaryl CoA reductase (HMGR) mRNA levels significantly increased in the rapid stages of follicle development, suggesting that SREBP-2 controls the biosynthesis of cholesterol in follicles. LDL receptor and LDL receptor related protein 1 mRNA also tended to increase with follicular development, however, expression of LDL receptor relative with eight ligand binding repeats (LR8) was only slightly affected by SREBP-2. Liver X receptor alpha (LXR alpha) was expressed in chicken follicles; its expression patterns corresponded with SREBP-2 gene expression. These results suggest that SREBP-2, which might be regulated by LXRalpha, is involved in the rapid growth stages of follicle development in avian species.
Seol
Hyang Sook
HS
Graduate School of Agricultural Science, Tohoku University, Sendai, 981-8555, Japan.
Sato
Kan
K
Matsubara
Yusuke
Y
Schneider
Wolfgang J
WJ
Akiba
Yukio
Y
D000818:Animals; D030161:Avian Proteins / Q000235:genetics; D002645:Chickens / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics; D008074:Lipoproteins / Q000235:genetics; D000071518:Liver X Receptors; D026503:Low Density Lipoprotein Receptor-Related Protein-1 / Q000235:genetics; D057093:Orphan Nuclear Receptors; D006080:Ovarian Follicle / Q000254:growth & development* / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D011973:Receptors, LDL / Q000235:genetics; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D051782:Sterol Regulatory Element Binding Protein 2 / Q000235:genetics* / Q000378:metabolism
D030161:Avian Proteins; D004268:DNA-Binding Proteins; C116062:LR8 protein, chicken; D008074:Lipoproteins; D000071518:Liver X Receptors; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D011973:Receptors, LDL; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D006903:Hydroxymethylglutaryl CoA Reductases