One important difference between Kluyveromyces species and S.
cerevisiae is glucose repression (also known as catabolite repression;
Gancedo, 1998) of galactose utilization. Some mechanisms of glucose
repression of the GAL genes are shared by S. cerevisiae and K. lactis but
there are also fundamental differences (for an extensive review see
Rubio-Texeira, 2005). In fact, the expression of the GAL/LAC genes
is not repressed by glucose in all K. lactis strains, and the extent of
catabolite repression in glucose-repressible strains is less pronounced
than in S. cerevisiae (Rubio-Texeira, 2005). This is expected to be also
the case in related species, such as K. marxianus, which are mostly
adapted to environments containing lactose and galactose. The characteristics
of the GAL genes promoters likely contribute to the less
pronounced glucose repression of galactose utilization in K. lactis
compared to S. cerevisiae. First, there are several binding sites for the
glucose-triggered transcriptional repressor Mig1p in the S. cerevisiae
GAL promoters, while in K. lactis there is only one corresponding
binding site (in the GAL1 promoter) (Rubio-Texeira, 2005). Moreover,
in K. lactis the expression of the GAL4 gene is autoregulated, since
its promoter contains a binding site to its own gene product, Gal4p,
which encodes a transcriptional activator involved in the regulation
of the GAL genes. Conversely, the S. cerevisiae GAL4 promoter does not
have any Gal4p binding site (Rubio-Texeira, 2005). Increased dosages
of the activator Gal4p in K. lactis may alleviate glucose repression
One important difference between Kluyveromyces species and S.
cerevisiae is glucose repression (also known as catabolite repression;
Gancedo, 1998) of galactose utilization. Some mechanisms of glucose
repression of the GAL genes are shared by S. cerevisiae and K. lactis but
there are also fundamental differences (for an extensive review see
Rubio-Texeira, 2005). In fact, the expression of the GAL/LAC genes
is not repressed by glucose in all K. lactis strains, and the extent of
catabolite repression in glucose-repressible strains is less pronounced
than in S. cerevisiae (Rubio-Texeira, 2005). This is expected to be also
the case in related species, such as K. marxianus, which are mostly
adapted to environments containing lactose and galactose. The characteristics
of the GAL genes promoters likely contribute to the less
pronounced glucose repression of galactose utilization in K. lactis
compared to S. cerevisiae. First, there are several binding sites for the
glucose-triggered transcriptional repressor Mig1p in the S. cerevisiae
GAL promoters, while in K. lactis there is only one corresponding
binding site (in the GAL1 promoter) (Rubio-Texeira, 2005). Moreover,
in K. lactis the expression of the GAL4 gene is autoregulated, since
its promoter contains a binding site to its own gene product, Gal4p,
which encodes a transcriptional activator involved in the regulation
of the GAL genes. Conversely, the S. cerevisiae GAL4 promoter does not
have any Gal4p binding site (Rubio-Texeira, 2005). Increased dosages
of the activator Gal4p in K. lactis may alleviate glucose repression
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หนึ่งที่สำคัญความแตกต่างระหว่าง kluyveromyces ชนิด S .
cerevisiae ปราบปรามกลูโคส ( ยังเป็นที่รู้จัก catabolite กดขี่ ;
gancedo , 1998 ) การใช้กาแลกโตส . กลไกของกลูโคส
ปราบปราม gal ยีนร่วมกันโดย S . cerevisiae และ K . lactis แต่
ยังมีความแตกต่างพื้นฐาน ( สำหรับการตรวจสอบอย่างละเอียดดู
รูบิโอเท็กเซร่า , 2005 ) ในความเป็นจริงการแสดงออกของยีน gal / ครั่ง
ไม่หักห้ามใจจากกลูโคสใน K . lactis สายพันธุ์ และขอบเขตของ
catabolite การปราบปรามในกลูโคสซึ่งอดกลั้นสายพันธุ์คือน้อยกว่า
กว่าของ S . cerevisiae ( รูบิโอเท็กเซร่า , 2005 ) นี้คาดว่าจะยัง
ในกรณีที่เกี่ยวข้องกับชนิด เช่น K . marxianus ซึ่งเป็นส่วนใหญ่
ดัดแปลงสภาพแวดล้อมประกอบด้วย แลคโตส กาแลกโตสและ . The characteristics
of the GAL genes promoters likely contribute to the less
pronounced glucose repression of galactose utilization in K. lactis
compared to S. cerevisiae. First, there are several binding sites for the
glucose-triggered transcriptional repressor Mig1p in the S. cerevisiae
GAL promoters, while in K. lactis there is only one corresponding
binding site (in the GAL1 promoter) (Rubio-Texeira, 2005). Moreover,
in K. lactis the expression of the GAL4 gene is autoregulated, since
its promoter contains a binding site to its own gene product, Gal4p,
which encodes a transcriptional activator involved in the regulation
of the GAL genes. Conversely, the S. cerevisiae GAL4 promoter does not
have any Gal4p binding site (Rubio-Texeira, 2005). Increased dosages
of the activator Gal4p in K. lactis may alleviate glucose repression
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