Lauter, F.-R., Marchfelder, U., Russo, V.E.A., Yamashiro, C.T., Yatzkan, E., and Yarden, O. 1998. Photoregulation of cot-l, a kinase-encoding gene involved in hyphal growth in Neurospora crassa. Fungal Genetics and Biology 8: 300 - 310. Blue light plays a key role as an environmental signal in the regulation of growth and development of fungi and plants. Here we demonstrate that in Neurospora crassa hyphae branch more frequently in cultures grown in light. Previous studies had identified cot-1 as a gene that controls apical hyphal cell elongation. In the cot-1 mutant, cessation of elongation is accompanied by hyper-branching, Here we demonstrate that the cot-1 gene encodes two transcript species of about 2100 nt (cot-1 (s)) and about 2400 nt (cot-1 (D) in length and that the ratio of both transcript species abundance is photoregulated. The origin of the difference between cot-1 (D) and cot-1 (s) was localized to the 5' end of the cot-1 transcripts, suggesting that two COT1 isoforms with different activities may be formed. Both light effects, on branching and on cot-1 expression, were dependent on functional wc-1 and wc-2 gene products. In addition to light, L-sorbose comprises another environmental cue that controls hyphal branching in N. crassa. In the presence of L-sorbose, photoregulation of cot-l was blocked, suggesting the involvement of alternative and potentially interdependent signaling pathways for the regulation of hyphal elongation/branching.
Bibliographical noteFunding Information:
We thank Amir Sharon for his critical comments on the manuscript. This work was supported in part by BARD (U.S.-Israel Binational Research and Development Fund). F-R.L. was supported by a fellowship from the European Molecular Biology Organization (EMBO, ASTF 7528).
- Alternative transcripts;
- Hyphal branching
- Neurospora crassa