ISSN:
1432-2145
Keywords:
Key words Profilin
;
Tobacco pollen
;
Nicotiana tabacum
;
cDNA cloning
;
Isoforms
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Profilins are actin-binding proteins in eukaryotes which participate in the phosphoinositide pathway via binding to PIP2. Using polyclonal rabbit sera raised against plant profilins, the occurrence of several profilin isoforms is demonstrated in two-dimensionally analyzed tobacco pollen extracts. The cDNAs coding for two novel tobacco profilin isoforms (ntPro2, ntPro3) were isolated from a pollen cDNA library by antibody screening. When the cDNA and deduced amino acid sequences of the two isoforms were compared with a previously isolated tobacco pollen profilin cDNA (ntPro1), significant differences were noted in the non-coding regions, whereas the coding sequences, in particular the functional domains, showed little variation. The cDNAs coding for the three tobacco profilin isoforms were expressed in Escherichia coli and shown to bind comparably to different anti-profilin antisera. The high degree of similarity among the different tobacco pollen profilin isoforms points to functional equivalence. Assuming that the presence of profilin is indispensable to the control of the large amounts of actin present in pollen, the occurrence of different profilin isoforms in pollen is interpreted to represent a protective mechanism against loss of profilin functions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004970050022
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