@article{zhirnov_wollenzien_2003, title={Action spectra for UV-light induced RNA-RNA crosslinking in 16S ribosomal RNA in the ribosome}, volume={2}, ISSN={["1474-9092"]}, DOI={10.1039/b208677h}, abstractNote={UV irradiation induces intramolecular crosslinks in ribosomal RNA in the ribosome. These crosslinks occur between nucleotides distant in primary sequence and they are specific, limited in number and have crosslinking efficiencies sufficient to allow their use in monitoring conformational changes. In this work, the frequency of crosslinking for eight 16S rRNA crosslinks was determined as a function of wavelength of irradiation. For six of the crosslinks, the action spectra correspond to the absorption spectra of at least one of the participating nucleotides. For a crosslink between nucleotides C967 and C1400 the maximum frequency of crosslinking occurs at wavelengths blue-shifted from the absorbance maximum of cytidine and for a crosslink between C1402 and C1501 the maximum frequency of crosslinking is red-shifted. Photoreversal of the crosslinks was also studied by deproteinizing crosslinked RNA under mild conditions and then re-irradiating it with specific wavelengths under conditions in which the crosslinks were reversed but not formed. The different crosslinks exhibit significantly different extents of photoreversal versus wavelength profiles. The differences in the crosslinking action spectra can be accounted for in the absorbance spectra of the nucleotides that are involved in the crosslink as well as by the photoreversal action spectra.}, number={6}, journal={PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES}, author={Zhirnov, OV and Wollenzien, P}, year={2003}, pages={688–693} }
 @article{huang_wu_su_zhirnov_miller_2001, title={A novel role for bone morphogenetic proteins in the synthesis of follicle-stimulating hormone}, volume={142}, ISSN={["1945-7170"]}, DOI={10.1210/en.142.6.2275}, abstractNote={FSH is produced in pituitary gonadotropes as an α/β heterodimer, and synthesis of the β-subunit is the rate-limiting step in overall FSH production. Synthesis of FSHβ can be regulated by activin and inhibin, both of which are members of the transforming growth factor-β superfamily. Bone morphogenetic proteins (BMPs) also belong to the transforming growth factor-β family and are multifunctional growth factors involved in many aspects of tissue development and morphogenesis, including regulation of FSH action in the ovary. Here we report a novel function for BMP-7 and BMP-6 in regulating FSH synthesis in the pituitary. Using primary pituitary cell cultures derived from transgenic mice that carry the ovine FSHβ promoter linked to a luciferase reporter gene (oFSHβLuc), BMP-7 or BMP-6 was found to stimulate oFSHβLuc expression by 6-fold. Transient expression of the oFSHβLuc in a transformed gonadotrope cell line, LβT2, was induced 4-fold by BMP-7 or BMP-6 treatment. More importantly, BMP-7 and BMP-6 increased endogenous FSH secretion by 10- and 14-fold, respectively, from LβT2 cells, demonstrating for the first time that a functional signaling BMP system is present in gonadotropes. Two bioneutralizing antibodies to BMP-7, which cross-react with BMP-6, but not with activin A, decreased basal oFSHβLuc expression and FSH secretion from transgenic mouse pituitary cultures by 83–88% and 47–48%, respectively, suggesting an autocrine or paracrine role for BMP-7 or BMP-6 in FSH synthesis. Neither bioneutralizing antibody to activin A or activin B decreased basal oFSHβLuc expression or mouse FSH secretion significantly. Dose-dependent inhibition of FSH synthesis by anti-BMP7 was also observed in rat and sheep pituitary cultures. These results combined with the fact that the messenger RNAs for BMP-7 and BMP-6 were detected in mouse pituitaries and LβT2 cells indicate that BMP-7 and/or BMP-6 can function as FSH stimulators and may be significant physiological factors maintaining basal FSH expression in vivo.}, number={6}, journal={ENDOCRINOLOGY}, author={Huang, HJ and Wu, JC and Su, P and Zhirnov, O and Miller, WL}, year={2001}, month={Jun}, pages={2275–2283} }