Lactation transcriptomics in the Australian marsupial, Macropus eugenii: transcript sequencing and quantification.
BACKGROUND
Lactation is an important aspect of mammalian biology and, amongst mammals, marsupials show one of the most complex lactation cycles. Marsupials, such as the tammar wallaby (Macropus eugenii) give birth to a relatively immature newborn and progressive changes in milk composition and milk production regulate early stage development of the young.


RESULTS
In order to investigate gene expression in the marsupial mammary gland during lactation, a comprehensive set of cDNA libraries was derived from lactating tissues throughout the lactation cycle of the tammar wallaby. A total of 14,837 express sequence tags were produced by cDNA sequencing. Sequence analysis and sequence assembly were used to construct a comprehensive catalogue of mammary transcripts. Sequence data from pregnant and early or late lactating specific cDNA libraries and, data from early or late lactation massively parallel sequencing strategies were combined to analyse the variation of milk protein gene expression during the lactation cycle.


CONCLUSIONS
Results show a steady increase in expression of genes coding for secreted protein during the lactation cycle that is associated with high proportion of transcripts coding for milk proteins. In addition, genes involved in immune function, translation and energy or anabolic metabolism are expressed across the lactation cycle. A number of potential new milk proteins or mammary gland remodelling markers, including noncoding RNAs have been identified.
Lefèvre
Christophe M
CM
CRC for Innovative Dairy Products, Department of Zoology, University of Melbourne, VIC, 3010, Australia. c.lefevre@zoology.unimelb.edu.au
Digby
Matthew R
MR
Whitley
Jane C
JC
Strahm
Yvan
Y
Nicholas
Kevin R
KR
D000818:Animals; D020451:Contig Mapping; D030541:Databases, Genetic; D020224:Expressed Sequence Tags; D005260:Female; D020869:Gene Expression Profiling; D015723:Gene Library; D007774:Lactation / Q000235:genetics* / Q000502:physiology; D008018:Life Cycle Stages / Q000502:physiology; D007614:Macropodidae / Q000235:genetics*; D008321:Mammary Glands, Animal / Q000378:metabolism; D008892:Milk / Q000378:metabolism; D005810:Multigene Family; D011247:Pregnancy; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis*; D017423:Sequence Analysis, RNA
D011506:Proteins; D012333:RNA, Messenger