Cooperative actions of Tra2alpha with 9G8 and SRp30c in the RNA splicing of the gonadotropin-releasing hormone gene transcript.
In earlier studies, we demonstrated that excision of the first intron (intron A) from the gonadotropin-releasing hormone (GnRH) transcript is highly cell type- and developmental stage-specific. The removal of GnRH intron A requires exonic splicing enhancers on exons 3 and 4 (ESE3 and ESE4, respectively). Tra2alpha,a serine/arginine-rich (SR)-like protein, specifically binds to ESE4, although it requires additional nuclear co-factors for efficient removal of this intron. In the present study, we demonstrate the cooperative action of multiple SR proteins in the regulation of GnRH pre-mRNA splicing. SRp30c specifically binds to both ESE3 and ESE4, whereas 9G8 binds to an element in exon 3 and strongly enhances the excision of GnRH intron A in the presence of minimal amount of other nuclear components. Interestingly, Tra2alpha can interact with either 9G8 or SRp30c, whereas no interaction between 9G8 and SRp30c is observed. Tra2alpha has an additive effect on the RNA binding of these proteins. Overexpression or knock-down of these three proteins in cultured cells further suggests their essential role in intron A excision activities, and their presence in GnRH neurons of the mouse preoptic area further strengthens this possibility. Together, these results indicate that interaction of Tra2alpha with 9G8 and SRp30c appears to be crucial for ESE-dependent GnRH pre-mRNA splicing, allowing efficient generation of mature mRNA in GnRH-producing cells.
Park
Eonyoung
E
School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
Han
Jin
J
Son
Gi Hoon
GH
Lee
Mi Sun
MS
Chung
Sooyoung
S
Park
Sung Ho
SH
Park
Kyungsook
K
Lee
Kun Ho
KH
Choi
Sukwoo
S
Seong
Jae Young
JY
Kim
Kyungjin
K
D000818:Animals; D000906:Antibodies; D005091:Exons / Q000502:physiology; D005816:Genetic Complementation Test; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics*; D007031:Hypothalamus / Q000166:cytology; D007438:Introns / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D041681:NIH 3T3 Cells; D009474:Neurons / Q000502:physiology; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000276:immunology / Q000378:metabolism*; D012322:RNA Precursors / Q000502:physiology; D012326:RNA Splicing / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D011817:Rabbits; D000068103:Serine-Arginine Splicing Factors
D000906:Antibodies; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D010750:Phosphoproteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; C474542:Tra2alpha protein, mouse; D000068103:Serine-Arginine Splicing Factors; D007987:Gonadotropin-Releasing Hormone