Kluyveromyces lactissexual pheromones. Gene structures and cellular responses to α-factor

Abstract

The Kluyveromyces lactis genes for sexual pheromones have been analyzed. The alpha-factor gene encodes a predicted polypeptide of 187 amino acid residues containing four tridecapeptide repeats (WSWITLRPGQPIF). A nucleotide blast search of the entire K. lactis genome sequence allowed the identification of the nonannotated putative a-pheromone gene that encodes a predicted protein of 33 residues containing one copy of the dodecapeptide a-factor (WIIPGFVWVPQC). The role of the K. lactis structural genes KlMFalpha1 and KlMFA1 in mating has been investigated by the construction of disruption mutations that totally eliminate gene functions. Mutants of both alleles showed sex-dependent sterility, indicating that these are single-copy genes and essential for mating. MATalpha, Klsst2 mutants, which, by analogy to Saccharomyces cerevisiae, are defective in Galpha-GTPase activity, showed increased sensitivity to synthetic alpha-factor and increased capacity to mate. Additionally, Klbar1 mutants (putatively defective in alpha-pheromone proteolysis) showed delay in mating but sensitivity to alpha-pheromone. From these results, it can be deduced that the K. lactis MATa cell produces the homolog of the S. cerevisiaealpha-pheromone, whereas the MATalpha cell produces the a-pheromone.

Asymmetric mating behavior of isogamous budding yeast

“…Moreover, since at high densities/short distances it is similarly efficient as the best (MAT-type) symmetric strategy, the asymmetric behavior may not be counter selected during intratetrad mating or haplo-selfing, even considering potential benefits of this self-fertilization (12,38). The observed behavioral asymmetry is also likely to be common among ascomycetes including those with naturally haploid life styles, which all exhibit similar molecular asymmetry of the mating pathway (27,39,40).…”

Identification and characterization of the Komagataella phaffii mating pheromone genes

“… 2007 ; Ongay-Larios et al . 2007 ). All the identified proteins contain a C-terminal CAAX motif for farnesylation and were found to be essential for mating of a -type cells.…”

Engineering Kluyveromyces marxianus as a Robust Synthetic Biology Platform Host

“…The pheromones, derived from a -pheromone and α-pheromone precursor proteins, m ating f actor a (MFA1 and MFA2) and m ating f actor α (MFα1), are detected by their cognate cell surface recognition proteins and lead to polar morphogenesis or the formation of mating projections (“shmoo”) that can be used to deduce a strain’s mating type. We identified two putative K. marxianus MFA genes ( KmMFA1 and KmMFA2 ) as well as the MF α gene ( KmMFα1 , encoding two isotypes, Km MFα1 and Km MFα2) in the K. marxianus genome by reciprocal BLASTp using the S. cerevisiae and K. lactis protein sequences as queries ( 16 , 17 ) ( Fig. 1C ; see Fig.…”

“…We used reciprocal BLASTp using S. cerevisiae and K. lactis protein sequences as queries to identify two putative MFA genes ( KmMFA1 and KmMFA2 ), as well as the MF α gene ( 16 , 17 ). The sequences in S. cerevisiae are encoded by genes YPL187W and YGL089C in the Saccharomyces Genome Database ( 44 ), and those in K. lactis are encoded by GenBank entry CAG99901.1 (RefSeq ID XP_454814.1 ) and as described in reference 17 . To the best of our knowledge, these pheromones had not been previously identified in K. marxianus .…”