Need of X or Y chromosome protein after meiosis
X chromosome has many important genes required for general housekeeping. So we need not really talk about X-chromosome genes. Here is a list of genes present on the X-chromosome.

@Armatus, if all those genes were on autosomes then presence of Y wont be mandatory for male development. There are autosomal genes that are involved in sexual development for e.g. Anti-Mullerian Hormone gene is present on chromosome 19. However, there must be a master regulator that is male specific and since sex determination is chromosomal in mammals, the Y-chromosome must encode that master regulator. 

Sry, encoded in Y-chromosome, is one such protein that is absolutely essential for male sexual development. Having said that, it could be very well possible that the basic genes required in the process of spermatogenesis are autosomally encoded. In fact it is so. I just took the list of genes that were associated with sepermatogenesis in KEGG and checked their chromosomal locations. They are all autosomal.

Gene --- position
SPATA1  ---  1p22.3
SPATA25  ---  20q13.12
SPATA32  ---  17q21.31
SPATA9  ---  5q15
SPATA19  ---  11q25
SOHLH1  ---  9q34.3
SPATC1L  ---  21q22.3
SPATA18  ---  4q12
SPATA2  ---  20q13.13
SPATA21  ---  1p36.13
SPATA2L  ---  16q24.3
GMCL1  ---  2p13.3
SPATA7  ---  14q31.3
SPATA5  ---  4q28.1
SPATA6L  ---  9p24.2
SPATA4  ---  4q34.2
SPATA24  ---  5q31.2
SPATS2L  ---  2q33.1
SPATA16  ---  3q26.31
SPATA6  ---  1p33
SPATA12  ---  3p14.3
SPATS1  ---  6p21.1
SPATC1  ---  8q24.3
SPATA22  ---  17p13.3
SOHLH2  ---  13q13.3
SPATA13  ---  13q12.12
SPATS2  ---  12q13.12
SPATA20  ---  17q21.33
ASUN  ---  12p11.23
SPATA8  ---  15q26.2
SPATA17  ---  1q41
SPATA3  ---  2q37.1
SPATA5L1  ---  15q21.1
GMCL1P1  ---  5q35.3
SPATA41  ---  15q26.3
SPATA42  ---  1p13.3
SPATA33  ---  16q24.3