Profilin II is alternatively spliced, resulting in profilin isoforms that are differentially expressed and have distinct biochemical properties.
We deduced the structure of the mouse profilin II gene. It contains five exons that can generate four different transcripts by alternative splicing. Two transcripts encode different profilin II isoforms (designated IIa and IIb) that have similar affinities for actin but different affinities for polyphosphoinositides and proline-rich sequences. Profilins IIa and IIb are also present in humans, suggesting that all mammals have three profilin isoforms. Profilin I is the major form in all tissues, except in the brain, where profilin IIa is most abundant. Profilin IIb appears to be a minor form, and its expression is restricted to a limited number of tissues, indicating that the alternative splicing is tightly regulated. Western blotting and whole-mount in situ hybridization show that, in contrast to the expression of profilin I, the expression level of profilin IIa is developmentally regulated. In situ hybridization of adult brain sections reveals overlapping expression patterns of profilins I and IIa.
Lambrechts
A
A
Department of Biochemistry, Ghent University and Flanders Interuniversity Institute for Biotechnology, 9000 Ghent, Belgium.
Braun
A
A
Jonckheere
V
V
Aszodi
A
A
Lanier
L M
LM
Robbens
J
J
Van Colen
I
I
Vandekerckhove
J
J
Fässler
R
R
Ampe
C
C
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D003285:Contractile Proteins; D004305:Dose-Response Relationship, Drug; D005091:Exons; D020224:Expressed Sequence Tags; D006801:Humans; D017403:In Situ Hybridization; D007438:Introns; D008024:Ligands; D051379:Mice; D008840:Microfilament Proteins / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000494:pharmacology; D051304:Profilins; D011485:Protein Binding; D020033:Protein Isoforms; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014018:Tissue Distribution; D014158:Transcription, Genetic
D003285:Contractile Proteins; D008024:Ligands; D008840:Microfilament Proteins; C495741:PFN2 protein, human; C495739:Pfn1 protein, mouse; C495740:Pfn1 protein, rat; C495742:Pfn2 protein, mouse; C495743:Pfn2 protein, rat; D019269:Phosphatidylinositol 4,5-Diphosphate; D051304:Profilins; D020033:Protein Isoforms