Loci affecting flagellar assembly and function map to an unusual linkage group in Chlamydomonas reinhardtii.

Abstract

The unil mutant of Chlamydomonas reinhar*i lacks one of the paired flagella seen in wild-type cells.The missing flagellum is cis to the eye spot and at this site the basal body is incomplete, lacking a transition zone. Together with nine other loci affecting flagellar assembly and two loci affecting flagellar function unil defines an '100-centinorgan linkage group with a circular map. Measurements of gene-centromere distances on the uni linkage group are consistent with the ordering of loci determined by recombination analysis and place the centromere near pf29, a motilitydefective mutant. In well-synchronized meiotic cycles, recombination frequencies between loci on the uni linkage group but not loci on other linkage groups show striking temperature sensitivity during a 1-to 2-hr period 5 days before meiosis. The mutant strain pf7 has short flagellar stubs; pf8 totally lacks flagella. Mutants pf10 andpf29 have full-length flagella but the mutant cells exhibit abnormal motility. Cells ofpf 10 show little linear movement and tend to travel in small irregular circles; in liquid culture they form a tight pellet.

Mode of centriole duplication and distribution.

“…Several mutants affecting basal body structure and function, the uni linkage group, have now been described in the algae Chlamydomonas (Dutcher, 1986;Ramanis and Luck, 1986). Probes recognizing uni DNA sequences have been localized to basal bodies, and are consistent with the presence of two copies per cell (Hall et al, 1989).…”

Chlamydomonas reinhardtii: Biological Rationale for Genomics1

“…unknown IC69 Kamiya, 1988Mitchell and Kang, 1991Kamiya, 1988Kamiya, 1988Wilkerson et al, 1995Kamiya, 1998Sakakibara et al, 1991Pazour et al unpublished Pazour et al unpublished Casey et al, 1998Huang et al, 1979Huang et al, 1979 , 1993Perrone et al, 1998Yang and Sale, 1998Taillon et al, 1992Dutcher et al, 1988King et al, 1994King and Dutcher, 1997King and Dutcher, 1997Huang et al, 1979 See below altered waveform Huang et al, 1982aHuang et al, 1982aHuang et al, 1982aHuang et al, 1982aPiperno et al, 1994 Central pair micro- Barsel et al, 1988Barsel et al, 1988Barsel et al, 1988 Asleson and Lefebvre, 1998 Asleson and Lefebvre, 1998 Asleson and Lefebvre, 1998 Asleson and Lefebvre, 1998 Asleson and Lefebvre, 1998Kuchka et al, 1987Kuchka et al, 1987Kuchka et al, 1987McVittie, 1972Dutcher, 1986Dutcher, 1986Dutcher et al, 1988McVittie, 1972McVittie, 1972Ramanis and Luck, 1986: Holmes et al, 1992Dutcher et al, 1988<...>…”

CHLAMYDOMONAS REINHARDTII AS THE PHOTOSYNTHETIC YEAST

“…unusual feature of the uni linkage group is that it includes several mutations affecting flagellar function and assembly (71). Such a high degree of clustering of functionally related genes is unusual for eukaryotic chromosomes.…”